Trying to get full custody

[Proudstepmama]

Hey! I am new here so Iwill try to give a SHORT rundown of the going ons. Sorry my spelling is horrible!
 To start I am the Sm. My  hubby and I met a bout a week after he got bm preggy. She moved. We didnt believe this could be his child. Took us over a year to get her to agree to a DNA tst. Got it back and we have had more htan joint custody ever since. Before the test were back we went and got sd and had her for 3 weeks (bm didnt really know Dh except over the internet) We went through a year of this having the sd for 75 % of the time, but still paying bm full time child support. Finally we got fed up becuase she wouldnt keep a scedule so we went to court. Got it set up that we had her every weekend and all summer. First year of this the agreement was switched we had her during the week. Bm would nto get her on some weekends and we ended up having her all summer. Still paying full child support to bm to this day. It is now right, we have made bm take responsibility this year.
  Anyway a few months ago, bm desided she wanted to move. Over 3 hours away. We were able to put a stop to it and now she hates us. She only goes by the agreement and we get no extra time (while we had her we always gave her extra time especially on the holidays) She wouldnt let us even have her for thanksgiving even though bm didnt even cook a turkey or see familiy. Sd came to us and said that we forgot to pick her up and grammy and pappy were making her turkey. sd is 4 now by the way. Anyway we are still paying the same in child support which i dont think is right, The bm is on ssi so we have to pay 100% of her care at the bms plus the care of her here. We also have 2 other children, the bm has none.
   We are fed up with the situation and want to take her back to court and get full custody, she puts stuff in sds head and its really bugging us because you shoudl never use a child that way. But My main question is can we supeona her medical records to use in court? She is constantly telling us monthly that she has to have this test done or that test done and that she is going to die. (I believe she wants to move either becuase she is addicted to pain meds or they want to kick her off ssi) Could we get these records to show that she is unstable or that she is not well enough to care for a child?