Am I legally able to get custody of my goddaughter?

My Goddaughter is 2 now and her mother and I have been friends up until recently when we disagree on her wrong decision making. She makes decisions like sleeping with guys and getting pregnant not spending her money in a way to care for her kids and not cleaning and caring for them properly. I have spent hundreds of dollars on lice treatment because she wouldn't take care of their house and hair through the week, I have spent money making sure my goddaughter has diapers, wipes, toys, all her necessities at points and also have kept her on weekends pretty much since she was 5 months old. DHR took her from her mother and my family and I did everything we could to push her to do the right things or do the right things ourselves for her to get her back. She has been in the care of her mother since and things have progressively went down hill with her new boyfriend and their new baby what can i do legally to change my situation of her mother not allowing me to see her?