I would deal with this in a very, very sensitive way. From your viewpoint - not fair and not on about seeing your little girl, you should be able to do this and she should let you really, if there are no concerns.
From her viewpoint - hurts like a mad hell for a woman to be with a baby alone when she is still in love with the father (possible in your case) and then it hurts like crazy, mad hell when he finds someone else. Most women, who cherish their children more than anything do not really want them to come into any kind of contact with their ex's new woman, especially if they still have feelings for him. So.....see it from her viewpoint (if this is indeed how she feels?) but know that in order for you to have access, you need to tread carefully. I would firstly reassure her that you and only you will be spending time with your child (at first, let her get used to the idea that you are with someone else) and just go from there.
If she really won't budge or even communicate one bit, then unfortunately you'll have to go through a legal process. Good luck x
