Respectfully, your question is a tad confusing. If the lawyer is still on the case, s/he should be answering your questions or concerns.
Also, it is hard to tell you what the next step would be when we do not know to whom the letter was addressed.
I suggest you contact the clerk for the judge in charge of the case. Here in WI, some judges will intervene when nonrepresented persons write a letter explaining their situations. Perhaps, your judge would do so, as well. The judge's clerk will know if the judge would be receptive to a letter from you regarding this issue. If so, I would suggest explaining the hardships you are enduring without your car, how long you have been without it, etc. I would also point out that, if there is evidence in the car, the government could easily remove or othewise preseve that evidence, and return the car to you.