Freezer and fresh food sides not staying cool.

If you truely have a leak in the system that would need to be properly taken care of if you ever want to return to normal operation. If the defrost timer goes bad usually you will completely freeze up the coils which causes air circulation problems and only the very lowest part of the freezer (and sometimes fridge) sections will freeze. The upper top of the unit won't be very cold. Same thing happens if the evap. fan (above the coils) goes out (no air circ.).