Depends on how bad the leak is. Does there appear to be a lot of corrosion around the edges of the radiator or near the leak area? Really it can go either way. Your best bet is to locate a radiator shop near you and take it in. They will be able to be more specific.
It's probably cheaper in the long run and for reliability to replace the radiator. On a 2WD it's a 2.7 hour labor operation to replace the radiator. I would say $200 to $300 for a radiator $25 for antifreeze/coolant.