I have bank statements stating I paid for a car in full but let my ex put it in her name and use it while we were together, can I get it back?

That depends - what were the terms on which you let your ex use the car?  Was it a gift, or was your agreement that she could have it under her name and use it only as long as the two of you were together?  Given the change in title, it appears to be a gift, and thus irrevocable.