had the engine been used previously? if so, whoever installed it for you probably didn't take the head off and change the gasket.
if you're losing coolant, check for leaks. if its not leaking, and coolant is circulating, then it's pretty much for sure your head gasket.

 

I found out that its the water pump.... its leaking water/Coolant. Will I need to change the entire thing or just a hose? Any one know the price range?

 

if you dont know how to change a timing belt, youre going to be paying for labor as well. expect to pay 200-700. you should do the timing belt at the same time, since they have about the same lifetime, and if the belt breaks, you will need a new head. and you have to take the belt off to do the water pump anyway.