How can I sue someone in milwaukee,wi if I don't know their address, they won't comply n neither car insured?

I was in an accident.Someone ran a red light while I was going through a green light that was green for a while.I received the police reprt with her info,but it didn't have the correct address becuse the letter I sent to her returned.I called her but she is not complying.I don't want to sped lots of money becuase she may not comply to pay back if I can't serve her.I want to get her licwnse suspended but its looking like its going to be hard.She is completely at fault.She suggest that she won't and can't pay