Car Stall problems of the 2006 Toyota RAV4

I own 2006 Toyota Rav4 with 48,000 miles. My car was driving fine until christmas eve this year. Last year in April I received recall letter saying I should replace the oil rubber hose. 18 months later I notice a lot of oil under my car, there was none left in the engine. I had to call towing company to take the car to the dealer. They said that the hose is broken, the one that supposed to be upgraded lasted only 18,000 miles. They charge us $700 because our warranty finished in July 2011 and the warranty for the recall is only for 1 year. I tried to negotiate with them but nobody even listened. We left the dealer with nothing, my husband was driving the car, he pulled to the parking lot and heard this big noise coming from the engine. It was 15 minutes after we left the dealer service department. My husband called the right away and they said that they tested this car and everything was fine but if we want we can bring the car back. We had to call for towing company again. The car came back to the same dealer and they admitted there is a noise but for them to even look at the engine they have to charge us $1200. I have already called the Toyota customer service and they sending me back to the dealer to talk to their customer relation manager. The manager said he did some investigation and my problem with the engine is not connected with the repair they did. I talk to many different mechanics outside of Toyota and the said it is impossible for engine to just die. Besides every mechanic says the hose should last much longer than 18 months and they believe that it was not installed the right way. Toyota main office says the support the dealer decision and there is nothing they can do. I don't know what to do. They don't feel any responsibility for this situation. You have more experience with that, maybe you can give me some advice. Thank you.