You ended by earning a good grade, so I'm not sure what you could "report" her FOR. Merely accusing you? There's no rule against that. And sometimes professors DO have to rely on the reports of TAs. That's partly what TAs are for, to keep an eye on students during exams. The TA may have been wrong -- possibly it was even a case of mistaken identity -- but he or she didn't do anything out of bounds by reporting a suspected case of cheating.
It's a bit too late to do anything. However, did you save the email in which the accusation was made? My suggestion would be to speak to the department head about what happened. The oddest thing is that the accusation was made to you, but it didn't go anywhere, and I'm wondering why. Possibly, the other girl also indicated that she didn't know you and the TA or professor realized that there'd been an error. In any case, it would be worth just letting the department head or departmental director of undergraduate studies know about it, in the event the professor has been behaving erratically or oddly. It happens.