I am a law school graduate. What I offer is mere information, not to be construed as forming an attorney client relationship.
Okay, if he has this solid proof, the charge will most likely be dismissed (make sure it is off his credit report too just in case they have it in his record). As to what he can do, she cannot be charged with perjury unless she took the stand or made her testimony under oath (in court or in deposition). He can charge her with abuse of process, possible defamation, possible false accusations.
If he was arrested, he would sue under an abuse of process theory.
You need to hire a lawyer to defend this in court if you havent done so already AND you need a civil litigator to sue this person who made the false accusations.
To do this, try attorneypages.com or your state bar association (call 411). Once you get a hold of bar association, ask for lawyer referral. In either case, once you find a lawyer, check their record of discipline with the state bar association.
Hope this helps.