The first thing you need to do is seek all proper and required medical care. After you have taken care of your immediate needs you should consult with a few lawyers who handle premise liability cases on a contingency fee basis and hire the one that you feel most comfortable with.
I don't really understand your question. Charging decisions are made by individual prospector's offices, which can be a solicitor's office, district attorney's office or U.S. Attorney's office. Each office has their own policies. What specifically are you trying to find out?