when the water pump start to leaks alot,would the heater be gone also.

 

no the heater wouldn't fail...but scince it takes it heat from the coolant well then you might c a drop in the heat from inside the car...depending on how bad the leak is...either way get that water pump fixed befor u overheat the engine and start looking for swaps...

 

A low coolant level is why the heater isn't working well.

Change the timing belt too since it has to come off to change the water pump anyway.