The problem here is that if the order was issued, then the court found truth in her assertions. You don't say the sttus of the restraining order, which is important. It is hard to win a slander or defamation suit since you must show damages beyond the fact that you have the restraining order. You would have to show that clients left you solely because of it or you lost your job/income specificly because of it, etc. I would advise you to focus on beating the restraining order before you worry about suing her.
Yes, focus on contesting the restraining order rather than on the civil suit. If you have not yet had the extension hearing, hire a lawyer and contest extension of the order. You have the right to cross examine witnesses against you and present your own evidence at the extension hearing. Note also that even though a restraining order is a civil court order, violation of the civil court order carries a criminal penalty and the holder of the order cannot waive the terms of the order, i.e. if she asks you to come over and you go over, you have violated the order, her invitation is not a defense. Good luck.