Actually, that pump is a non-critical item. Mine had short-circuited and was causing the climate-control unit to shut down to protect itself, and the fix was simply to disconnect the electrical connection to the pump. The purpose of the pump is to pump the coolant when the engine is idling - above idling, the coolant flows sufficiently for heating purposes.

So if you are in a pinch, I believe that you can just find an elbow connector for the two hoses, and just bypass the pump, since your pump is leaking. In my case, the pump was not leaking, so I simply disabled the electrical connection, and my heating system works fine.