Welcome, Intel!
When I was first trying to figure out what the Watchtower meant to my family and marriage, google led me to the marriage articles at freeminds.org. Please see these, if you haven't already.
It's a difficult choice you face. Consider what is better for your daughter: trying to stick it out (growing up with conflict and tension in the family), or leaving your wife (with all the issues of divorce and a young child). I can't say which is better.
In my case, I stuck it out as long as I could--meaning until I was served with the divorce papers. I don't know if that was the best choice, but it was the best I could do at the time. And that's what should guide you, too: do what you think is best for your daughter, whatever that may be. She's the innocent one, the defenseless one, and that's why she comes first.
I'll add that counseling is a good idea, especially if your wife will go too. This means an impartial, professional counseler of course--not the untrained elders who, however well-meaning they may be, sympathise with a Witness more than an "Apostate".
So do the best you can, and know you are not alone.