Well, in many cases, the first thing you'd want to do is talk to the employer and try to resolve the problem informally. If that doesn't work, or if you know that that would be a useless exercise, you can contact a lawyer. In fact, it is often a good idea to consult with a lawyer before trying to negotiate with an employer concerning your ADA rights. You would explain to the EEOC why you believe that you have been discriminated against and they would investigate the claim of discrimination. Alternatively, you can contact a local bar association, and often they will have referral services that will direct you to an attorney practicing in the relevant area, though sometimes the referral service charges you a small fee.
Many private attorneys handle employment discrimination cases on a contingent fee basis.
It's often difficult to gauge a lawyer's degree of expertise yourself. The idea behind getting referrals is that you are being directed to someone who specifically knows this area of the law. I was wondering if you could describe a clear-cut case of discrimination. Then she comes in for an interview and the interviewer sees that she uses a wheelchair. We are afraid that someone who uses a wheelchair may have difficulties getting around and we think it's in the best interest of you and the students that you look for work somewhere else.