A.H.
If you are at all able to move - just do it. If it's a large enough complex that you can move to a different building, then give the landlord the opportunity to move you to a comparable apartment (if it's big enough, sometimes they are owned by larger managment corporations that own more than one complex too - something might be able to be arranged there). Otherwise, I'd look into the legal rights of breaking your lease under these circumstances.
It seems to me from your description that they've made it pretty clear to her that you're the one who's made the complaint. So she knows it's you and is taking her chances to make your life worse. Maybe she blames you that she's going to have to move? Whatever the reason, from her perspective she doesn't see that she's doing anything wrong and she's not going to stop. In fact, it may get worse. I'd get out, and quick.
Meanwhile, I agree with the suggestions to try and block the noise for your daughter. I had luck with an air filter in my son's room for white noise when I was trying to dull the noise of the rest of the house during his naps. He had the tendency to wake at the tiniest little noise and it seemed to do the trick in getting him to sleep through the night for us.
Good luck!