Overheating replaced coolant reservoir tank

My car started overheating. I saw a leak coming from the bottom so I took it to Jiffy lube to get an oil change and they told me it was the tank reservoir that needed to be replaced, but I said no because it was way too expensive. I took it to a different shop and they told me the same thing. They replaced my coolant tank, but it still leaked the coolant only this time it leaked more than before. I cannot drive for more than half a mile or else it starts overheating and the coolant is completely gone. Can some one please help?