Well first off if she's already seeing a therapist consult the therapist about what to do considering her alcoholism. They should be able to help the most.
If she's unwilling to do that I found a website that should help alot as I've never personally dealt with alcoholism. On ehow look up the article how to recover from alchol abuse.(I can't post the link) As the website says. See a doctor, admit the problem, and take it from there. So read the website and get some advice from it. There are alot of different reasons why someone can be an acholic so be careful the website tries to list all the ways to recover. But if you two consult a professional they will help you to find a way that's specialized to her problems.
The one thing that I can offer is that if she dosn't change but keeps expressing a desire to then you should leave, you'll feel like your abandoning her but sometimes people like this need a wake up call. And by staying with her even though you act like a good influence in her life, regardless of your actions, your presence is a negative influence. Because that safety of you, the subconscious approval that your still with her, encourages her to stay the same. If you do leave though be honest, you still love her but just can't deal with her alcholism and why you can't. I don't think you'll need to leave if she's actively trying to recover but just keep that in mind incase things change. I hope that helps, good luck.
And counselling for molestation dosn't help much if she's an alcholic. So deal with the alcholism first, get a therapist for that, and then deal with the molestation.