For a temp fix you can use Bar's Stop-Leak, available at just about any parts store. It's a suspended copper mix that plugs most cooling system problem areas, once you replace the radiator, you should do a complete coolant flush, however, b/c once your hole is plugged, should you develop another, it would be better to know it than to have the stop-leak do it's thing again and leave you unaware [at least that's how i'd prefer it]. Any 'ole parts or radiator store should be able to get you a suitable replacement, I haven't had a problem with any radiator I've gotten that was aftermarket any more than I have from one that was 100% OEM.