Question on antifreeze leakage?

I bought a 1994 Mazda Navaho last year and everything checked out okay but I have been having radiator problems ever since. I paid a mechanic $300 to have it fixed and he put some new hoses on it I believe and a new water pump. I drove it 40 miles and still had radiator leaks. I just put some radiator leak in it and it's been okay until this winter. I again was making a trip and checked the antifreeze and nothing again. I put more antifreeze in and it took it all on my trip home. I stopped into a mechanic shop and they were too busy and I took it to another one and they said I had a broken head gasket and heads. Well today I was driving it and it completely stopped and the battery light came on. I had it towed and a guy looked at my oil and there was no water in it (sign of a blown head gasket) and I've had no large amount of white moisture coming from the exhaust. It's been normal. What would your guess be what is wrong? I put a new battery in this past summer and I am guessing the alternator. I don't have alot of money for repairs as I am disabled. There has got to be a radiator leak somewhere. I am not too happy with the people I bought this vehicle from.