Though I've not had to deal with this problem personally I've seen it up close and personal because my sister's first husband is a drunk.
I agree with the people who say use tough love. It doesn't sound like your wife wants to get help for her problem (which she does have) so there's nothing you can do to stop it. It doesn't matter why she drinks too much, it only matters that she does. Drunks will always chose their drinks over the people who love them. For the sake of your kids, get out of there as soon as you can. If your wife can admit she has a problem and will sincerely try to get over it then by all means stick with her but from the way you've made it sound that's probally not the case. Call me as cold hearted as you want to but get rid of her now before you get dragged down even further. Whatever you do, DO NOT buy a house with this person. I can promise you that will end bad.
I really am sorry if I seem like a jerk here but I swear I'm just trying to do what's best for you. I've seen this in real life and up way to close. Lose her before you lose yourself. I know with love you're supposed to be willing to do that but what's the point if you're not going to save her? Besides, your kids need at least one sane parent so it might as well be you.
Back down the bullies to the back of the bus
Its time for them to be scared of us