What a strange law. I never heard about a law that you could get away with rape if you marry the victim. If it's rape, that means the victim didn't want to be a part of it. This implies to me that the victim certainly shouldn't have any desire to marry the rapist!
In terms of punishment, I really like what I have learned about Norway's correctional system. I've seen a couple documentaries about them. It seems like the prisons there are really focused on having a positive, respectful environment. The prisoners are prepared to return to society and do good things. I think imprisonment is a good punishment for rape.