It's either on the fuel rail itslef with a return line to the tank, or under the car near the fuel tank right after the fuel filter. Given that you have a 96, it's most likely under the car.
Did your mechanic tell you the exact reason it failed smog? I wouldn't replace the fuel pump, just the FPR if he says it's important. I would give the car a good tune up (spark plugs, spark plug wires, even front O2 sensor) before you replace the fuel pump.