You should speak with your lawyer for clarification. I think the problem is not what you "can do" but rather what is "practical to do." The guy that hit you is responsible for ALL of your damages if it was his fault. However, absent a pile of money or assets that can easily be collected via a judgment, most cases are limited to the amount of insurance coverage the guy has. What I assume your lawyer is trying to explain is that HE will not spend money out of HIS pocket to sue the guy individually because of concerns that there wont be any actual money recovered or the cost and risk of getting it is too high. BY example, you look at a guy with 2 houses and say "he's rich ....he can pay" where as a lawyer, who you are asking to spend thousands or tens of thousands of his own dollars out of pocket to put on a trial, may think "but those houses are in foreclosure and he will simply file bankruptcy" as too high of a risk.
If you truly want the lawyer to file suit, get a judgment for full value, etc., its your right to do that, BUT you may have to fund that litigation, because you DONT have the right to make others spend thier money to do so. Many times, if you are willing to pay the expenses, the lawyer WILL file suit and try your case. The one thing you should consider BEFORE you do this though, is that when a professional won't invest in your case because of concerns about getting value back, you should be equally reluctant and take a hard look at the decision. Much like deciding to bet on a horse your bookie tells you is a bad play vs. betting on a horse your bookie recommends and which he has bet his own personal money.