It's highly unlikely that the cable is available separately, you would need to purchase the entire wire harness that it is a part of. Your best option is to remove the bad terminal and install a new one. There are universal ones available at parts stores, however getting them to work well can be tough. Without seeing the situation, it is hard to give specific advice. You may be able to find a 02 Focus in a wrecking yard and cut the needed part of the harness and splice that into your car.
Good Luck!