There are two issues you may need to address. The first is the parenting plan and the second is the order of child support.
A court may modify an existing parenting plan if the child has been integrated into your home with the mother’s consent in substantial deviation from the current parenting plan. If your son has been with you for a year, then that is likely sufficient to establish integration into your home in substantial deviation from the parenting plan.
If there is an existing order of child support requiring you to pay support to the child’s mother, that order remains in effect until you get a new one entered. If the Division of Child Support is collecting or enforcing the current child support order, they will continue to do so until told otherwise by a court order. If you request a modification of the parenting plan, you can also request that the court modify child support to reflect the new parenting plan.