Its time to have a frank and open talk with your daughter - adult to adult. Explain that you will do all you can to help her but ultimately she has to take responsibility for her life and that of her baby and learn to fend for herself. I'm not saying give her a "sort yourself out or else" ultimation but she has to be made aware of the way her actions effect the rest of the family.

Its great that she knows she can come home to you but she is a grown up now.