I can't say that I've heard of anyone ever getting a loan on equity in a car.. That seems like a pretty risky move to make for any bank unless it's some kind of collector car that never gets driven.

Sell the car, save the cash, buy something cheap off one of those lots that will give loans to high risk borrowers, make double payments on it if you can to mitigate the amount of interest that you will be paying, get a secured credit card from your bank and start using it. With the car loan and the card you should be able to build your credit back to reasonable levels within a year.