Coolant leak?

So, we were on our way back to Washington State from California, I was driving just past the California border into Oregon. It was a big hill. My car started struggling as it was weighed down, and then it was like the radiator blew out or a radiator hose. It got really hot really fast. It seemed to have no power or very little power. When I pour water in, and a few seconds later it starts coming out somewhere near the dash/back upper engine, but not in a place I can reach. Any advice on what the problem could be, I poured a whole gallon of water in and just as fast, it all came dripping out, looks like it is coming from (looking from the front end) the upper back of the engine. About 8-12 inches down and about 8-12 inches from the dash.