How do I get an Attorney Ad Litem for my daughter?

My daughter will be 17 in a little over a month, and she has one year left at her dad's. She has a knee that has given her problems and he took her to the doctor once. She has done what the doctor said but her knee still hurts and good out. Her stepmother told her to tell me to take her to the urgent care on my weekend. I don't have insurance, they do. I'm willing to pay half of the Co-pay, but they won't take her again. They also haven't taken her to the eye doctor in over two years. I took her and paid for everything, get eyes had changed a lot. I offered them a copy of the prescription but they wouldn't take it. I feel she needs someone to stand up for her rights. How do I get this done?