Hi,
Well , to go out and buy a new TX/RX, motor, and esc you will be spending as much or more than what you paid for the boat. I'll guess you spent $70.00 plus another $70+ and you still have a toy-grade boat.
You will be better off buying a hobby-grade boat like a Proboat, Traxxas, Atomic, Aquacraft from a reputable local hobby shop or Horizon Hobby or Tower Hobbies where they stand behind what they sell.
Good Luck.