Hi, it depends if she co-signed on the loan, or if the loan is in her name. Did you have a loan? If so, and she is tied to the loan, that could explain why her name is on the title.
If you paid cash for the vehicle, and there is no reason that her name is on the title, and you are certain that you did not give permission for her name to be on the title, you could perhaps bring a lawsuit against her to remove her name from the title.
It is a little complicated, and I don't think anyone can really give you advice without looking at your specific facts and your contract. If you compile all your information, at that point, you should try to have an attorney look at the contract you signed when you purchased the vehicle.
If you are over 60, you can call CLEAR, which is volunteer civil legal service for the elderly: Persons 60 or over may call CLEAR*Sr at 1-888-387-7111 or TTY - 1-888-201-9737, regardless of income.
They may not be able to help you as they target basic needs such as housing, income, medical care and family safety, but it may be worth a try.
Otherwise, I encourage you to seek an attorney to assist you with your problem. Good luck.