I am a single mom of a 12 yo, only daughter/child and I really understand your concerns, and I applaud you as well for being so concerned.
When I was pregnant and facing the very real possibility that my DD's dad would be absent because he was at that time acting like a real jerk, having affairs, getting drunk, etc.
I read studies where girls with absent dad's ran a higher risk of making poor choices because of the love they did not receive from their own dad's and they are prime targets of preditors because of this emotional need.
So I made it my life's duty at that time to get her dad to be a dad, and to bond with her. Even at one point going to where he was playing, walking up on stage during the middle of a song and demanding that he give me money for formula/diapers. LOL I also chased him and his girlfriend down onetime in his car and handed him my baby in her car seat and said "your turn", then drove away.
He did end up becoming a good dad to her, so our story ended up okay, although not as good as it would be if we were still together and she didn't have to live in two separate homes with two separate families.
My thoughts are to keep the good communication that you have with her going. And continue to be a stable, loving force in her life. She is going to need you in the years to come in a big way. Also let her take the lead in her communication attempts with her dad. Neither hinder, nor encourage it...just support her and always try to keep the channels of communication open between you and she. Be a safe place for her to go to, as she probably is very sad about her dad's seemingly lack of care for her.
It's sound like you are a fine mom and I just wanted to let you know that.