Do I have a bad water pump or is there a bigger issue?

I have a 1989 Jeep Comanche that I recently purchased. A few days ago, the truck suddenly started running hot (dummy light in cab came on). I pulled the truck over, bought some coolant at the gas station I was at, and filled the reservoir tank and let the truck cool. Once the engine cooled, I started the truck and drove across the street to an Advance and bought a thermostat, gasket, and gasket sealant. I drove the truck about 3 miles down the road, and it started getting hot again. After allowing the truck to cool one more time, I drove it home, about a 10 minute trip. The engine light did not come on for the first 5 minutes or so, but the truck died as I was nearing the hill near the house. I let the truck coast so I wouldn't have to restart it, and only turned it over to get enough gas into it to get over a small bump in the road that I couldn't coast over (which the truck was hesitant to restart, but when it turned over there seemed to be no power lost), then killed the engine. It has been parked for 4 days. I have replaced the radiator hoses, thermostat, thermostat housing (the first cracked when I replaced the thermostat). Now, when we fill the radiator with water/coolant, it is leaking out somewhere around the lower hose or water pump, but not the radiator. We are going to get new hose clamps tomorrow and see if the clamp is not getting tight enough (it's an original clamp, which we're replacing with the screw-in clamp). If the leak does not stop here, am I simply looking at a cracked water pump, or is this something that could be much worse?