Take a cab to midtown manhattan (cheap flat rate). Have breakfast in any quaint restaurant you find. Go window shopping along 5th avenue. Catch an early dinner at "One if by Land, Two if by Sea" near 7th and Bleeker in the Village (that will be your most expensive thing.)

If you don't like that, stroll around central park for a while, take a cab to the ferry building and go to the Statue of Liberty...hope this helps.