If you go before the judge, the court generally has a list of qualified individuals who may act as a guardian ad litem. The judge will simply take the next name on the list and make the appointment. It's that easy.
NOTE: This answer does not create an attorney-client relationship and it meant for information purposes only. I am not licensed in NJ and therefore can only speak in broad terms and not state-specifics. You should consult with a licensed professional in your state.