Engine Oil Leaking problems of the 1996 Toyota Corolla

I purchased the car October, 2000 as a used car with a warranty. About two weeks later the car broke down and had to be towed to dealer that I bought it from. A rebuilt engine block was put in because of major oil problems. It took over a month for them to finish the repair. I was assured that it was ok. About 5 months later the car started leaking oil and I had to constantly watch the oil level. I was told by the same dealer that it was normal to have to watch the oil on a car that old. I got more concerned and called another dealer and was told that it was not normal so I took the car back to the dealer. I insisted that the car be looked at. Again the engine block had to be replaced as something was not put on correctly (that is the excuse they gave me). This took about 2 weeks to repair. Again I was assured that the car would last this time. The engine was under warranty at this time. Three months later the engine light went on so I took it back again. They fixed that problem but I am not sure what they did at that time. I drove the car just over a year and just this week the car started smoking. I took it to the dealer and was told that there was major work on the engine that needed to be done but the warranty was out. It will be very expensive to fix it and so they did not want to do it. Now I have a car that does not run without smoking and I still owe $7000 on it. I am very upset because it seems that they sold me a car with major problems that they never could fix.