Refinance car?

[stephlove]

My FI and I made a not so great decision last fall (okay, TERRIBLE decision) when we traded in his junk car for a newer car. Both of us had bad credit, and bought the new car with an INSANE interest rate at 15.67%.

In the last 7 months, both of us have worked our asses off and have raised our credit scores from the 500's to the higher 600's.

I'm not sure how auto loans work, but is there a way to refinance them? I'm pretty sure we could get a way better interest rate now than we had before. I'm just trying to figure out some way to make this completely stupid purchase turn out for the better.