try Zadies Kosher Bake Shop, 19-09 Fair LAwn Ave, Fair Lawn..phone # 201-797-6565.
Their cakes, as well as everything else, isdelicious. My husband is a caterer and they order from there frequently. As far as cost, I have no clue, but it won't be cheap. Another suggestion, if you are trying to save some $$, and it does not have to be Kosher, is to call Stop and Shop or Whole Foods in Ridgewood and price out a cake there.