You should definitely file a claim with the EEOC for age discrimination in violation of the Age Discrimination in Employment Act ("ADEA"). Also, if you believe that you lost your permanent status due to discrimination on the basis of age, you can request reinstatement.
(Unfortunately, not being a permanent employee is not a protected characteristic, so as long as you being made non-permanent wasn't itself discriminatory, you would not have a separate basis for a discrimination suit based on your employee status).
You can file a charge with the EEOC using the instructions available online here:http://www.eeoc.gov/employees/charge.cfm
The EEOC will investigate your complaint and either file suit on your behalf or issue you a right to sue letter so you can pursue your claim against your employer through a private attorney.
If the principal has made false and damaging statements about you outside of LAUSD then you can sue the principal individually for defamation of character. However, it seems to me that the more appropriate people to sue would be the ones (if there are) who actually made the false complaints about you alleging misconduct with a student and racist statements.
Other than age discrimination, your cause of action against LAUSD is pretty limited, since it's very difficult to sue a county employer for defamation. Also, bear in mind that you would have to prove that the allegations being made against you are false in order to prevail on such a cause of action.
I'm not clear on LA Promise's role, but if they have reccommended your termination or done anything to encourage your termination, you may have a cause of action against them for intentional interference with economic relations. Otherwise, I don't see much else you can sue against them.
I hope the above information is helpful.
Please let me know if you have any additional questions.