While its admirable that you want to "help", what you may not be aware of is you may not be helping her. Instead, it sounds more like you want to do something because of your own need to do something because of some other driving force.
My respecftul suggestion is you allow the person to do as they wish about the situation. You may not know all of the circumstances involved or the motivations of each party.
What you can do is support her and suggest she see a rape counselor and/or a religious counselor and be there for her as a friend. Mostly, she needs to know she is still okay and has you as a friend. Don't force her into a situation into which she does not wish to go.
Good luck to both of you.