I would like to buy a coop in NJ, the problem is that there is a money judgment against me, can the creditor levy my share in the coop

Because a judgment creditor can theoretically levy the coop, the co-op board will not approve you as a buyer due to the judgment.  Moreover, a lender will not likely give you a mortgage.  You need to deal with the judgment.  Make a plan to pay it and get it removed.