<PAGE>   1
                                  EXHIBIT 10.2


East Bay Regional Office                                Date: September 11, 1997
1331 N. California Blvd.
Suite 320
Walnut Creek, Ca. 94596-9504

                                            Borrower: New Arts Acquisition, Inc.

    Subject: CREDIT TERMS AND CONDITIONS ("AGREEMENT")

    Gentlemen:

    To induce Imperial Bank (herein sometimes herein referred to as "you" and
sometimes as "Bank") to make loans to the undersigned (herein called
"Borrower"), and in consideration of any loan or loans you, in your sole
discretion, may make to Borrower, Borrower warrants and agrees as follows:

    A.  Borrower represents and warrants that:

        1. EXISTENCE AND RIGHTS. Borrower is a Delaware Corporation. Borrower is
           duly organized and existing and in good standing under the laws of
           the State of Delaware (without limit as to the duration of its
           existence); Borrower has powers and adequate authority, rights and
           franchises to own its property and to carry on its business as now
           conducted, and is duly qualified and in good standing in each State
           in which the character of the properties owned by it therein or the
           conduct of its business makes such qualification necessary; and
           Borrower has the corporate power and adequate corporate authority to
           make and carry out this Agreement. Borrower has no investment in any
           other business entity except as follows:

           (a) Pinnacle American Realty Tax Services, Inc.
           (b) Pinnacle American Realty Tax Service of New York, Inc.

        2. AGREEMENT AUTHORIZED. The execution, delivery and performance of this
           Agreement are duly authorized and do not require the consent or
           approval of any governmental body or other regulatory authority; are
           not in contravention of or in conflict with any law or regulation or
           any term or provision of Borrower's articles of incorporation,
           by-laws, or Articles of Association, as the case may be, and this
           Agreement is the valid, binding and legally enforceable obligation of
           Borrower in accordance with its terms.

        3. NO CONFLICT. The execution, delivery and performance of this
           Agreement are not in contravention of or in conflict with any
           agreement, indenture or undertaking to which Borrower is a party or
           by which it or any of its property may be bound or affected, and do
           not cause any lien, charge or other encumbrance to be created or
           imposed upon any such property by reason thereof.

        4. LITIGATION. To the knowledge of Borrower (i) there is no litigation
           or other legal proceedings pending or threatened against Borrower,
           which individually or in the aggregate would have a material adverse
           effect on the financial condition, operations, or business of
           Borrower; and (ii) Borrower is not in default with respect to any
           order, writ, injunction, decree or demand of any court or other 


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<PAGE>   2
        governmental or regulatory authority, where such default would have a
        material adverse effect to the financial condition, operations or
        business of Borrower.

    5.  FINANCIAL CONDITION. The Recasted and Forecasted Income Statement,
        Summary Cash Flow & Dividend Analysis, Proforma Balance Sheets, Cash
        Flow Forecast and Financing Analysis of Borrower, copy of which has
        heretofore been delivered to you by Borrower, and all other statements
        and data submitted in writing by Borrower to you in connection with this
        request for credit are prepared in good faith based upon reasonable
        assumptions, and have been prepared in accordance with generally
        accepted accounting principles on a basis consistently maintained.

    6.  TITLE TO ASSETS. Borrower has good title to its assets.

    7.  TAX STATUS. Borrower has no liability for any delinquent state, local or
        federal taxes, not subject to dispute by Borrower and for which
        reasonable reserves have been established and, if Borrower has
        contracted with any government agency, Borrower has no liability for
        renegotiation of profits.

    8.  TRADEMARKS, PATENTS. Borrower, as of the date hereof, possesses all
        necessary trademarks, trade names, copyrights, patents, patent rights,
        and licenses to conduct its business as now operated, without any known
        conflict with the valid trademarks, trade names, copyrights, patents and
        license rights of others.

    9.  REGULATION U. The collateral for this loan is not margin stock within
        the definition of Regulation U of the Board of Governors of the Federal
        Reserve system.

B.  Borrower agrees that so long as it is indebted to you, it will, unless you
    shall otherwise consent in writing:

    1.  RIGHTS AND FACILITIES. Maintain and preserve all rights, franchises and
        other authority adequate for the conduct of its business; maintain its
        properties, equipment and facilities in good order and repair; conduct
        its business in an orderly manner without voluntary interruption and, if
        a corporation or partnership, maintain and preserve its existence.

    2.  INSURANCE. Maintain public liability, property damage and workers'
        compensation insurance and insurance on all its insurable property
        against fire and other hazards with responsible insurance carriers to
        the extent usually maintained by similar businesses.

    3.  TAXES AND OTHER LIABILITIES. Pay and discharge, before the same become
        delinquent and before penalties accrue thereon, all taxes, assessments
        and governmental charges upon or against it or any of its properties,
        and all its other liabilities at any time existing, except to the extent
        and so long as:

        (a) The same are being contested in good faith and by appropriate
            proceedings in such manner as not to cause any materially adverse
            effect upon its financial condition or the loss of any right of
            redemption from any sale thereunder; and

        (b) It shall have set aside on its books reserves (segregated to the
            extent required by generally accepted accounting practice) deemed
            adequate with respect thereto.


                                       2

<PAGE>   3
        4. PROFITABILITY.  Borrower, on a consolidate basis with National
           Insurance Group ("Guarantor") to be profitable on a fiscal year basis
           and shall not have losses for any two consecutive quarters.

        5. NOTICE OF DEFAULT.  Promptly notify the Bank in writing of the
           occurrence of any event of default hereunder or any event which upon
           notice and lapse of time would be an event of default.

        6. BANKING RELATIONSHIP.  Maintain, and cause all its subsidiaries to
           maintain, all significant bank deposit accounts and banking
           relationship with Bank.

        7. COSTS AND FEES.

           (a) Borrower shall pay to Bank all legal fees, documentation costs
               and all out of pocket cost and expenses incurred by the Bank in
               connection with the negotiation and preparation of this
               Agreement, including but not limited to filing fees.

           (b) Borrower will pay promptly to Bank without demand, after notice,
               with interest thereon from the date of expenditure at the rate
               applicable to the loan from Bank to Borrower, reasonable
               attorneys' fees and all costs and expenses paid or incurred by
               Bank in collecting or compromising any loan whether or not suit
               is filed. If suit is brought to enforce any provision of this
               Agreement, the prevailing party shall be entitled to recover its
               reasonable attorneys' fees and court costs in addition to any
               other remedy or recovery awarded by the court.

        8. EXCESS CASH FLOW PRINCIPAL PAYMENTS.  Commencing April 1, 1999, and
           on the 91st day of each fiscal year thereafter, pay to Bank as a
           principal reduction of any loan made by Bank to Borrower, an Excess
           Cash Flow Principal Payment ("ECFPP") equal to Excess Cash Flow
           ("ECF") times Principal Payment Percentage ("PPP"). For the purpose
           of this Section 8 the following definitions shall apply:

           (a) "CFBD" means the Guarantor's audited net income after tax, plus
               depreciation, amortization, plus (less) changes in working
               capital, less principal and interest payments on all debt, less
               capital expenditures. CFBD excludes any cash received from
               financing activities (i.e. new loans, new equity and other forms
               of financing). In addition, CFBD shall not include amounts
               reported on Guarantor's consolidated statements of cash flows as
               reported in its SEC financial statements representing proceeds
               from the sale, maturity or purchase of investment securities, as
               reported in accordance with Generally Accepted Accounting
               Principals.

           (b) "MDA means $0.48 times the number of Guarantor's common shares
               outstanding as of any fiscal years.

           (c) "ECF" means the difference between CFBD and the MDA measured on
               an annual basis on the 91st day following each fiscal year end.

           (d) "ECFPP" means the annual payment to be made by Borrower as a
               reduction in the principal of the obligations owing Bank from
               Borrower paid in accordance with the provisions of this Section
               B.8.



                                       3

<PAGE>   4
            (e) "PPP" means the percentage of ECF to be paid by Borrower each
                year to Bank in accordance with the provisions of this Section
                B.8. The PPP's for each year is set forth in Schedule A attached
                hereto. 

        9.  REPORTING REQUIREMENTS. Borrower will provide the following to Bank,
            all in form and substance satisfactory to Bank:

            (a) Commencing with the fiscal year 1999, and each year thereafter
                no later than the 91st day of each fiscal year, a certificate of
                the calculation of ECF, certified to by the Chief Financial
                Officer of the Borrower. The calculation shall set forth, in
                reasonable detail, the method of determining ECF and such other
                variables as are relevant in determining the ECFPP, as estimated
                in the attached Schedule A. 

            (b) Cause the Guarantor to provide those reports required by Section
                7 of the Credit Terms and Conditions executed by Guarantor in
                favor of Bank dated April 2, 1997, ("Guarantor's Credit
                Agreement"), as such may be amended, modified, superseded,
                replaced, restated or modified even if the Guarantor's Credit
                Agreement is terminated or no longer in effect for any reason.

        10. USE OF PROCEEDS.  Borrower shall use the proceeds of any loan from
            Bank only to purchase the assets of American Realty Tax Services,
            Inc. ("Seller") and American Realty Tax Services of New York
            pursuant to the terms of that Asset Purchase Agreement ("Purchase
            Agreement") dated as of August 15, 1997 between Seller, Borrower and
            Guarantor.

        11. PURCHASE AGREEMENT.  Prior to the Bank making any loans to Borrower,
            Borrower shall provide Bank with an executed copy of the Purchase
            Agreement.

        12. GUARANTEE. Prior to Bank making any loans to Borrower, Borrower
            shall cause Guarantor to execute a guarantee in form, substance and
            amounts satisfactory to bank guaranteeing Borrower's obligations to
            Bank and Bank shall have received an Amendment to the Pledge
            Agreement executed by Guarantor and an amendment to the Guarantor's
            Credit Agreement.

        13. NET WORTH. Maintain, on a consolidated basis with Guarantor and
            Guarantor's and Borrower's subsidiaries, a tangible net worth
            (meaning the excess of all assets, excluding any value for good
            will, provided that good will for Borrower will be included,
            trademarks, patents, copyrights, leaseholds, organization expense
            and other similar intangible items, over its liabilities) of not
            less than $25,000,000 to increase each fiscal year end, commencing
            with fiscal year end 1997, by Guarantor's net income minus dividends
            paid.

        14. CASH FLOW COVERAGE.  Commencing with fiscal year 1997 and thereafter
            on an annual basis, the aggregate sum of Borrower's and Guarantor's
            net profit plus period depreciation divided by the current portion
            of long term debt and capitalized leases shall not be less than 1.4.

        15. QUALIFICATION TO DO BUSINESS.  Within 90 days from the date of this
            Agreement qualify as a foreign corporation to do business in
            California.   


                                       4

<PAGE>   5
C.   Borrower agrees that so long as it is indebted to you, it will not,
     without your written consent:

     1.   TYPE OF BUSINESS; MANAGEMENT. Make any substantial change in its
          business or operations or make any change in incumbency of Mark A.
          Speizer as chairman and Chief Executive Officer of Borrower or of
          Bruce A. Cole as President of Borrower.

D.   The occurrence of any one of the following events of default shall, at your
     option, terminate your commitment to lend and make all sums of principal
     and interest then remaining unpaid on all Borrower's indebtedness to you
     immediately due and payable, all without demand, presentment or notice, all
     of which are hereby expressly waived:

     1.   FAILURE TO PAY. Failure to pay any installment of principal or of
          interest on any indebtedness of Borrower to you within 10 days of the
          date when due.

     2.   BREACH OF COVENANT. Failure of Borrower to perform any other term or
          condition of this Agreement, or any other agreement or document
          executed by Borrower in favor of Bank, binding upon Borrower, which
          failure continues and is not cured within thirty days after written
          notice from Bank to Borrower.

     3.   BREACH OF WARRANTY. Any of Borrower's representations or warranties
          made herein or any statement or certificate at any time given in
          writing pursuant hereto or in connection herewith shall be false or
          misleading in any material respect.

     4.   INSOLVENCY; RECEIVER OR TRUSTEE. Borrower or Guarantor shall become
          insolvent; or admit its inability to pay its debts as they mature; or
          make an assignment for the benefit of creditors; or apply for or
          consent to the appointment of a receiver or trustee for it or for a
          substantial part of its property or business.

     5.   JUDGMENTS, ATTACHMENTS. Any money judgment, writ or warrant of
          attachment, or similar process shall be entered or filed against
          Borrower or Guarantor or any of its assets, which judgment, writ or
          warrant of attachment or similar process will have a material adverse
          effect on the financial condition, operations and business of
          Borrower or Guarantor and which remains unvacated, unbonded or
          unstayed for a period of 30 days or in any event later than five days
          prior to the day of any proposed sale or execution under such
          judgment, writ, warrant of attachment or similar process.

     6.   BANKRUPTCY. Bankruptcy, insolvency, reorganization or liquidation
          proceedings or other proceedings for relief under any bankruptcy law
          or any law for the relief of debtors shall be instituted by or
          against Borrower or Guarantor and, if instituted against it, shall be
          consented to.

     7.   REVOCATION OF GUARANTEE. The revocation of any guarantee by the
          Guarantor.



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<PAGE>   6
    8.  DEFAULT BY GUARANTOR. An event of default shall occur in the Guarantor's
        Credit Agreement as such may be amended, modified, superseded, replaced
        or restated, or modified or in any other agreement or document executed
        by Guarantor in favor of Bank.

E.  Miscellaneous Provisions.

    1.  FAILURE OR INDULGENCE NOT WAIVER. No failure or delay on the part of
        your Bank or any holder of Notes issued hereunder, in the exercise of
        any power, right or privilege hereunder shall operate as a waiver
        thereof, nor shall any single or partial exercise of any such power,
        right or privilege preclude other or further exercise thereof or of any
        other right, power or privilege. All rights and remedies existing under
        this agreement of any note issued in connection with a loan that your
        Bank may make hereunder, are cumulative to, and not exclusive of, any
        rights or remedies otherwise available.

    2.  TERMINATION. Upon thirty days written notice to Lender, Borrower may
        terminate this agreement in full, provided that, upon such time of
        notice and upon the effective termination date, the Borrower has no
        outstanding principal, interest, penalties, or any other amounts due
        under this agreement. Upon termination, Lender's interest in all
        Collateral of Borrower shall cease.

    3.  NOTICES. All notices, demands, requests or other communications that
        may be or are required to be given, served, or sent by any party to
        any other party pursuant to this agreement shall be in writing and
        shall be mailed by first-class registered or certified mail, return
        receipt requested, postage prepaid, or transmitted by hand delivery,
        with signature required by recipient, addressed as follows:

        Notices to Borrower:

                   Gregory S. Saunders
                   Chief Financial Officer
                   New Arts Acquisition, Inc.
                   395 Oyster Point Boulevard, Suite 500
                   South San Francisco, California 94080-1933

        With a copy (which shall
        not constitute notice) to:

                   Robert P. Barbarowicz
                   Secretary
                   395 Oyster Point Boulevard, Suite 500
                   South San Francisco, California 94080-1933
 
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<PAGE>   7
          Notices to Bank:

               Joseph J. McCarthy, Vice President
               Imperial Bank
               East Bay Regional Office
               1331 N. California Blvd.
               Suite 320
               Walnut Creek, Ca 94596-9504
               Atten: Commercial Lending

          Each party may designate by notice in writing a new address to which
          any notice, demand, request or communication may thereafter be so
          given, served or sent. Each notice, demand, request or communication
          that is mailed shall be deemed sufficiently given, served, sent, and
          received for all purposes at such time as it is delivered to the
          addressees (with the return receipt, the delivery receipt, the
          affidavit of messenger being conclusive evidence of such delivery) or
          at such time as delivery refused by the addressees upon presentation.

F.   Applicable Law and Reference Provisions

     1.   APPLICABLE LAW.  This Agreement and all other agreements and
          instruments required by Bank in connection therewith shall be governed
          by and construed according to the laws of the State of California, to
          the jurisdiction of which the parties hereby agree to submit.

     2.   REFERENCE PROVISIONS.

          (a). Other than (i) non-judicial foreclosure and all matters in
               connection therewith regarding security interests in real or
               personal property; or (ii) the appointment of a receiver, or the
               exercise of other provisional remedies (any and all of which may
               be initiated pursuant to applicable law), each controversy,
               dispute or claim between the parties arising out of or relating
               to this Agreement which controversy, dispute or claim is not
               settled in writing within thirty (30) days after the "Claim Date"
               (defined as the date on which a party subject to the Agreement
               gives written notice to all other parties that a controversy,
               dispute or claim exists), will be settled by a reference
               proceeding in California in accordance with the provisions of
               Section 638 et seq. of the California Code of Civil Procedure, or
               their successor section ("CCP"), which shall constitute the
               exclusive remedy for the settlement of any controversy, dispute
               or claim concerning this Agreement, including whether such
               controversy, dispute or claim is subject to the reference
               proceeding and except as set forth above, the parties waive their
               rights to initiate any legal proceedings against each other in
               any court or jurisdiction other than the Superior Court in the
               County where the real property securing this Agreement, if any,
               is located or Los Angeles County if none (the "Court"). The
               referee shall be a retired Judge of the Court selected by mutual
               agreement of the parties, and if they cannot so agree within
               forty-five (45) days after the Claim Date, the referee shall be
               promptly selected by the Presiding Judge of the Court (or his
               representative). The referee shall be appointed to sit as a
               temporary judge, with all of the powers of a temporary judge, as
               authorized by law, and upon selection should take and subscribe
               to the oath of office as provided for in Rule 244 of the
               California Rules of Court (or any subsequently enacted Rule).
               Each party shall have one peremptory challenge pursuant to CCP
               Section 170.6. The referee shall (a) be requested to set the
               matter for hearing within sixty (60) days after the Claim Date
               and (b) try any and all issues of law or fact and report a
               statement of decision upon them, if




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<PAGE>   8
               possible, within ninety (90) days of the Claim Date. Any decision
               rendered by the referee will be final, binding and conclusive and
               judgment shall be entered pursuant to CCP Section 644.90 in any
               court in the State of California having jurisdiction. Any party
               may apply for a reference proceeding at any time after thirty
               (30) days following notice to any other party of the nature of
               the controversy, dispute or claim, by filing a petition for a
               hearing and/or trial. All discovery permitted by this Agreement
               shall be completed no later than fifteen (15) days before the
               first hearing date established by the referee. The referee may
               extend such period in the event of a party's refusal to provide
               requested discovery for any reason whatsoever, including, without
               limitation, legal objections raised to such discovery or
               unavailability of a witness due to absence or illness. No party
               shall be entitled to "priority" in conducting discovery.
               Depositions may be taken by either party upon seven (7) days
               written notice, and request for production or inspection of
               documents shall be responded to within ten (10) days after
               service. All disputes relating to discovery which cannot be
               resolved by the parties shall be submitted to the referee whose
               decision shall be final and binding upon the parties. Pending
               appointment of the referee as provided herein, the Superior Court
               is empowered to issue temporary and/or provisional remedies, as
               appropriate.

          (b). Except as expressly set forth in this Agreement, the referee
               shall determine the manner in which the reference proceeding is
               conducted including the time and place of all hearings, the order
               of presentation of evidence, and all other questions that arise
               with respect to the course of the reference proceeding. All
               proceedings and hearings conducted before the referee, except for
               trial, shall be conducted without a court reporter, except that
               when any party so requests, a court reporter will be used at any
               hearing conducted before the referee. The party making such a
               request shall have the obligation to arrange for and pay for the
               court reporter. The costs of the court reporter at the trial
               shall be borne equally by the parties.

          (c). The referee shall be required to determine all issues in
               accordance with existing case law and the statutory laws of the
               State of California. The rules of evidence applicable to
               proceedings at law in the State of California will be applicable
               to the reference proceeding. The referee shall be empowered to
               enter equitable as well as legal relief, to provide all temporary
               and/or provisional remedies and to enter equitable orders that
               will be binding upon the parties. The referee shall issue a
               single judgment at the close of the reference proceeding which
               shall dispose of all of the claims of the parties that are the
               subject of the reference. The parties hereto expressly reserve
               the right to contest or appeal from the final judgment or any
               appealable order or appealable judgment entered by the referee.
               The parties hereto expressly reserve the right to findings of
               fact, conclusions of law, a written statement of decision, and
               the right to move for a new trial or a different judgment, which
               new trial, if granted, is also to be a reference proceeding under
               this provision.

          (d). In the event that the enabling legislation which provides for
               appointment of a referee is repealed (and no successor statute is
               enacted), any dispute between the parties that would otherwise be
               determined by the reference procedure herein described will be
               resolved and determined by arbitration. The arbitration will be
               conducted by a  retired judge of the Court, in accordance with
               the California Arbitration Act, Section 1280 through Section
               1294.2 of the CCP as amended from time to time. The limitations
               with respect to discovery as set forth hereinabove shall apply to
               any such arbitration proceeding.




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<PAGE>   9

AGREED TO AND ACCEPTED:


NEW ARTS ACQUISITION, INC.                  IMPERIAL BANK

BY /s/ GREG SANDERS, EVP      DATE 9/17/97  BY /s/ JOSEPH McCARTHY  DATE 9/17/97
  --------------------------      --------    ---------------------     --------
  (SIGNATURE AND TITLE)                       (SIGNATURE AND TITLE)

BY /s/ ROBERT P. BARBAROWICZ  DATE 9/17/97
  --------------------------      --------
  (SIGNATURE AND TITLE)
  EXECUTIVE VICE PRESIDENT &
    SECRETARY





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<PAGE>   10
<TABLE>
<CAPTION>
Schedule A                     Numbers in $000's                               Fiscal Year
                                                        -----------------------------------------------------------
Amounts herein are estimates only                         1998       1999        2000          2001           2002
and subject to change                                   ------     ------     -------     ---------      ---------
<S>                                                      <C>       <C>         <C>           <C>            <C>
                                                                                          
Total est. NAIG cash flow before dividends,             $3,413     $5,718     $ 8,459     $  12,812      $ 11,185
after debt service                                                                        
                                                                                          
Less Maximum Dividend Allowance (MDA)                    1,904      1,904       1,904         1,904         1,904
(based on $.48/sh.)                                                                       
                                                        ------     -----      ------      --------      ----------
Excess Cash Flow (ECF) available for                    $1,509     $3,814      $8,555       $10,908        $9,281
prepayment of term loan                                                                   
                                                                                          
Principal Payment Percentage (PPP)                        50.0%      30.0%       20.0%         10.0%         10.0%
                                                                                          
                                                        ------      -----     --------     --------      ---------
Prospective Excess Cash Flow Principal                   $ 754     $1,144      $1,311        $1,091        $  928
Payment (ECFPP)                                                                           
Cumulative prospective ECFPP                               754      1,899       3,210         4,300         5,228
                                                        ------     ------    -------     ---------      ---------     
</TABLE>