LostSister, welcome! You have received excellent advice so far. I'll add two things. First, pray for strength and help from your HP. Pray that your sister's eyes will be opened and she'll seek help. Secondly, work on YOU. Learn all you can, take care of YOU, and hopefully some day your sister will come to you telling you she can't go on with drinking and needs help. Don't do the work for her, but have the resources ready for her to call.
Think of a loving intervention too. It may not be the thing that gets her to seek help, but may stick in her mind. You have to go about it correctly so you don't alienate her, and there are books you can read.
But most importantly take care of you. As love to take down people!
Best wishes.