Legal Question in Credit and Debt Law in Florida

Unless you have a written agreement that provides that you retain a security interest in the car, no, you can't. As I read your question, the car is registered in her name. It's her car. She has the car, and you are stuck with the payments. If you stop paying, its probable the car will be repossessed, but you will be stuck with the deficiency balance. You should probably see an attorney about the viability of a lawsuit against her to recover money owed.