Thank you for using our forum. My name is ***** ***** I hope to assist you today.
The easiest, and most efficient way to deal with this situation is to have the seller apply to the DMV for a "duplicate title" - there will be a small fee and she can get the new title, then sign it over to you.
Make sure that the sale draft is in writing, and that you send her the request for the duplicate title in writing so that the transfer of title can be made due to her lack of title in writing. Keep copies of all of these for your records.
However, if she refuses to do this for you (she has an obligation to do so - she sold you a car she has an obligation to provide clean title), then you can sue her for "breach of contract" and ask the court to issue a judgment giving you title to the car.
You can explain to her that you are not asking her for any money in the lawsuit, but you must have the judgment to get the title.
(Most people when they learn that they will be sued, will go ahead and get you that duplicate title so you can get your title, and then get the vehicle registered properly).