I don't know if the OP is coming back but I know she has posted about her vehicles before. I think one had a $199 lease that she extended and another around $400.00
First OP, have you turned in one of the vehicles. Unless you both work full-time jobs on opposite sides of the state you should go down to one vehicle. We did it, best financial move we made. If you are a stay at home, there is absolutely NO reason why you need two cars.
Even if you have to take DH into work a few days a week it will be cheaper in the long run, and I just can't fathom how you are going to build credit with two high interest car loans with one income.
If I am totally off base and you are down to one car, the answer is based on which car is left, how much you have left and what they want you to refinance.
Bottom line, if you are that bad financially you need to buy an older reliable car, and try to do it outright. You could get a part-time job when DH is not working and just put all that money into an account and it will add up soon.
Good luck. I hope you come back and answer some of the questions.