Firstly, where is it leaking from? If its from the gasket seals around the water pump body, you can use rtv sealant to re-seal the water pump.
However, if it leaks from the pulley bearing, I'm afraid you will have to change the entire pump.
hey sorry but this is DIY garage ma ..... so not onli cars right ? anyone know hot to DIY electrical stuff ar ? .... my fish tank bubble pump runs one 2 big battery but i got nothing to do now wanna DIY something...