hi, babygirl.
I think you've done all that you can. Unfortunately alcoholism is a very personal, deep and consuming disease that can only be overcome with a lot of dedication.... when you're ready. It's deeply individual. You can support her and help her, but, in the end, the decision to stop drinking is her own... there is nothing you can do about that.
There has to be a time when you have to separate yourself from what is going on... for your own sake. I think that since you'll be leaving highschool soon and hopefully you'll be on to bigger and better things, you should be focussing on that. Do NOT sacrifice yourself because of this alcoholism. It is not yours to deal with.
There are many support groups and organizations available all over the world. Try googling some of them (I don't know the names off hand, but there will be so many). Coming to Ehealth was a great decision if you ask me. We're all here to talk to and to give advice!
Just be strong!