@BrandonEasley1985 - You have identified what you need to: get a judge to order her to give you the form 8332. It happens frequently. For how you go about it, you've asked a legal question and there are no lawyers here.
But, pick up on the info in CatinaT1's reply. You have a negotiating point with the mother. She may not realize that if she releases the dependency and child tax credit to you, she still gets to retain the Earned Income Credit and (if applicable) Head of Household filing status and the day care credit.
