What are my chances of getting a car loan with bad credit?

I have some bad credit (539 to be exact) working on rebuilding it all the bad stuff is really old and the current items are all good (other than medical bills) I am looking at a nice '01 Chevy Suburban for $5995. I have 2500 to put down, the lot that has the car is only wholesale I will have to go to a bank and try to get the rest but with about 40% down how good are my chances? Oh and I have a decent job and make around 50k a year...