Are you sure the USB ports themselves aren't working? It may be a controller on the board, or the circuit "surrounding" it. You need to trouble shoot those first. If you can determine that nothing is wrong, you then move on to replacing the ports themselves. Won't be an easy task since they are anchored very strongly and improper technique may damage (burn/flex) the board.
Of course you can send it out for repair, but then again you could be spending as much as the cost of a new board or even a used laptop.. after all it is a 5 years old machine, so you need to weigh your options.