You have an attorney. That is the person you need to talk to about this. There is no general rule about what your claim is worth. A lot will depend on your prognosis for recovery and the amount of insurance available to the defendant. These are things your attorney will be able to explore.
If you don't qualify for the public defender, you need to hire an attorney. This is one of the biggest problems you have in your life right now. It is going to affect you for some time. You need to do everything you can to borrow or raise the money to address it. Your other choice is to plead guilty and ask the Court for a lenient sentence. There really is no third option. You cannot win at trial representing yourself.
The problem with adding the wife to the lawsuit is that you would have to show that she did something wrong (you can't just sue people because they have more money - they actually have to have harmed you). In order to do this, you would have to have more facts than you outline above. Simply owning a car that is involved in an accident does not make you personally responsible for the damage. Letting your husband drive your car, without more, is not a wrongful act.
If it was negligent to...
You are borderline for being able to qualify for a Chapter 7. Your income might disqualify you - although the analysis is more complicated than can be addressed on this forum.
If you convert, you would likely lose the equity in the rental property. You can protect the equity in which ever property you live in, but if the rental can be sold for a net profit the Chapter 7 Trustee will do so.
A change in the law requires action from the state legislature. You will want to contact your state representative and your state senator (and perhaps the governor's office) to discuss legislative change.
You are facing a very serious charge. Second degree assault could result in 4-12 years in prison. It is something that you need to take very seriously. That said, you need a criminal defense attorney and there is probably a good chance that you can avoid prison time or significant jail time. A lot will depend on the circumstances and your case cannot be fully evaluated without looking at the prosecutor's file. Take a deep breath, hire an attorney, and put in the work necessary to put this...