Radiator Leaking

I have a 1995 chevy lumina with a 3.1L 6cyl engine. The radiator is leaking fluid from the bottom. If you look under the car there are two rubber stoppers at the bottom of the radiator. One on the driver side and one on the passenger side. The one on the passenger side is fine. The one on the driver side is gone though. Like its busted. Is there a way to just replace that instead of buying an entirely new radiator? And if so what is that part called?