Sick Goldfish? Help.?

I won a fish at the Del Mar Fair in SD on Sunday, and he was in a bag. He was completely fine that night, but then he started laying at the bottom of the tank, and at first we didnt have a filter or big fish tank for them so we had to put them in a little cage. and the next day we bought a tank. Waited 24hrs and put them in yesterday, but now today he is completely on his side breathing weird. Is it too late for my goldfish?? and if not what can I do?