2000 chevy malibu coolant leak? helpp?

[Rachael Bbb]

a few weeks ago my malibu started smoking white smoke on the drivers side, although the car wasnt over heated much. so i pulled over, checked the coolant, it was low so i filled it with water and later added the coolant. It was fine for about a week or 2, no smoke. But today it started smoking bad again although with no overheating again, i opened the hood and the smoke was coming from the back right side of the engine, tons of white smoke, i know its a coolant leak because i smelt it and i saw coolant on the ground, in quite a large puddle.
anyone know exactly where the leak might be and how much it will cost?