As far as abandoning someone who needs help: Print out a list of rehabs, AA meetings and local hospitals and give it to her when you talk to her.
She has a phone, right? If/when she wants help, she will have to get it herself - regardless of your goodwill and desire to help. This is 100% up to her.
By you helping her now the way you have been, you've actually been giving her a soft place to land when she drinks. The best chance for recovery for her is for you to let go and she will have to face the consequences of her own actions.
Be prepared for screaming and crying. Walk away anyway. It's the kindest thing you can do for both of you.