Week 1 - Mail out the petition for expungement to the court.
Week 6 - When the court mails back your petition, make photocopies of it. Mail out the photocopies to various New Jersey departments as required by law. You must use certified mail, return receipt requested.
Week 7 - When you get the return receipts back, mail them to the court.
Week 12 - The court will send you an order of expungement. Mail this order to the various departments.
For a more details, check out Expungement Process in New Jersey.