I am so sorry for your situation.  It is very difficult to give any real help in this type of forums but I will do my best.  I would, though, strongly suggest that you try and see if you qualify for legal aid or for any family law clinics that can help you with this matter.  Now, a cross-motion is just a regular motion asking for relief from the judge in the same case on the same day.  Generally it has a shorter service requirement on the other party.  So here is what you do:  use the same format as the motion that was served upon you.  Where it says "motion" type in "cross-motion."  In the body of the Notice of Motion put the same info: date and time, Judge, court room, part, court house address.  In the relief section - the part where they ask what you want the judge to order - indicate that you want the 7K as well.  Then in your affidavit write your story and state that you have complied albeit slowly and that he owes you.  Request that the Judge call it a wash. Hopefully the Judge will do just that.  Copy and show your proof of payment of the 3K and attach as an an exhibit.  Look at the affidavit of service on the motion and copy that as well.  Serve it on him and file the cross motion with it with the court.  Have it notarized. Good luck.