As @VolvoGirl stated so clearly, "Just file your return correctly with your dependents". If the IRS rejects your e-file attempt, then you will have to print and mail it.
At some point, the IRS will follow up, sending both of you letters. At that point, you can submit whatever court documents you have and IRS will decide who is eligible to claim the child on their tax return."
@Rlsu1
