Ideally as a relationship progresses we hope that we are able to work on shared goals as we move forward. However, this doesn't seem to be the case in your relationship right now. The behaviours such as those displayed by your girlfriend as you mentioned above are more often than not symptoms of something more troubling going on. You said that there is a child in her charge? Who is caring for this child living in squalor as she is out drinking? I'm not saying that your girlfriend can't go out and have a good time now & then, but her priorities seem a little skewed right now.

For the child, your and her sake... at the very least I think it's time you put your foot down with regard to the messiness & hygiene of your home, and try as best you can to get to the heart of what is really going on with her. This may not be something that you or her can fix on your own, but defining troubling issues that need addressing is half the battle won.

I wish you all the best.