What type of lawyer do I need to sue my ex-husband for the car we both financed before we got divorced?

The situation is, my ex-husband and I financed a car in 2009. He wasn''t approved for the loan so I decided to be the primary and he the secondary on the loan because that was the only way for him to be able to get the car. We were divorced in May of 2010 and the judge put in the divorce order that he is required to make the payments on the car. I called the bank and found out that he isn''t making the payments on the car. I tried to do a voluntary reposession on the car; however, he has to agree to the voluntary reposession. The car is going to be repossessed since he hasn''t made the payments on the car and it is going on my credit. This is ruining my credit and I am trying to find out what type of lawyer I need to sue him for the car and for the money to pay off the car since the divorce papers say he is responsible for it and I''m not. He isn''t keeping up with the divorce decree. I need help. Thank you.