My 1992 Dodge Caravan will not start!!!?

I left out of town for about two months and left the van sitting. When I came back into town it drove perfectly fine to go and pick up my wife and kids about twenty miles there and twenty miles back the other direction. I drove it for about another ten miles the next day and then I went to go get gas at the station. I immediately started the car and it began to act funny, kind of sputtering so luckily we were close to the home so I went back to the house and checked everything out. It looked as though the water was quite low. I thought possibly that there could have been water in the gas tank too considering that it happened right after I filled it with some gas. I drove it for maybe ten more mile, and only used it three seperate times. Each time I had to fill it up with water in order to drive it. Every time I stopped the van a lot of water would come out of the radiator, I mean a lot. I drove it to go and get groceries tonight and it would not start when I got in it to come back home. I tried stepping on the gas but there was no pressure and it kept sputtering and acting like it was but it would not start! It sounded like mini backfires when I was trying to start it...