I reside in NJ and was recently divorced, I forwent my ex's 401k to purchase my house, now I need to change the deed, do I need an attorney ?

I'm not sure based on the information you provided how you want the deed changed.  Did you, as part of the divorce, give up your rights to the 401(k) and your spouse gave up rights to the house?  There should be something in the judgment of divorce that outlines how that is to occur, and your ex will have to comply with changing the deed, if your ex does not, you will have to go back to court but then your ex will have to pay fees.  you should change the deed to protect yourself.