Hhhmmm...where to begin here...first of all, you have to life a life that suits you, in order to be a good Mother. You can't live life around trying to make your kid happy.
Secondly, there are no guarantees that he will get sober and life will become wonderful again. For many alcoholics, getting sober is just the tip of the iceberg.
Lastly, there is nothing wrong with saying "hey, I can't do this to myself anymore, much less to this innocent kid here, and I need to live a healthier life". It seems to me that we women, in general, tend to think we are in the wrong for standing up for ourselves. Why is that? Who says we have to stay married/living together/otherwise connected to someone who doesn't treat us well or take care of us and our children?
Lastly, you don't have to make any decisions right now. It seems you have alot to consider here, so maybe take everything one issue at a time, one day at a time. So for today, what could you do to make life a little better for you and your daughter?