Praise be to Allaah.
It is permissible for you to hire a lawyer if the company is indeed trying to put you off and is not doing what it should, and the expenses of this lawyer will be charged to them. This is not wrongdoing to them in this case. But with regard to the expenses of the accident and your medical treatment, do not take more from this company that the amount you have given them during the period when you have had insurance with them, because any additional amount is counted as ribaa (usury, interest) and it is not permissible for you to take it. As far as I know, insurance is compulsory for you [in the US]; if it was voluntary then you should not have been involved in these insurance contracts.