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.
1. Symmetric V-Shaped to Turbine & External Wastegate
Internal wastegate/actuator will release air at a maximum of how much boost pressure? 0.8, 1.2 bar? An option to increase boost levels is to use external...