How big a cage should a dwarf rabbit have?

I love my rabbit to death. I'm 15 and we got him when I was only 9 (He's 6) so I didn't know anything about rabbits. My parents wanted to get me a rabbit because they didn't want me to have a dog, which I wanted very much. They, like most people, thought that rabbits only lasted a couple years. But now that I'm older I love to read about rabbits and do research about the best ways to care for them and I've realize that my rabbit's cage is probably too small. Although he is very small and gets to go outside and run around for about 2 hours a day it's winter it's been too cold outside to let him out. (Or for me to do homework outside for 2 hours a day, lol) The rabbit cages that I have seen are about 100 - 200 dollars which I don't have so I was thinking that maybe I could wish for a bigger cage for Christmas. But I really have no idea how big is big enough. He only weighs about 4 pounds (last time he went for a checkup at the vet) and is maybe 7in from tail to nose or smaller. The cage will be indoors and it would be nice if it could be easily cleaned without spilling on the carpet, so any tips on that are more than welcome. Also, his current cage has a wire bottom, is that bad for their feet? If so, what other kinds of cage bottoms are there and which are best? Thanks for any help!~

A rabbits cage should be a minimum of 6 times the length of your bunny and should be able to stand upright on his back legs without hitting his head on the top of the cage.Really the bigger the cage the better so he can get more exercise.My dwarf lops live in banks males are 1.2metres long and females 1.5 metres long all are about 50cm high and 60cm wide. Sorry don't know conversion into inches. They are made out of melamine and are really easy to clean.Yes wire on the cage floor is bad as it can lead to sore hocks (back feet) best to get one with a flat floor. You can get ones with plastic floors.

It needs to be at the very least 8 square feet and tall enough for him to stand up all the way. He also needs at least 5 hours a day out of his cage. The cage needs to have a solid bottom. Here are some cage pics so you can see all the different cage optionshttp://www.binkybunny.com/BUNNYINFO/GreatHabitats/tabid/229/Default.aspx

The rule for rabbit cages at my house is for each pound they weigh they need a square foot of cage area. So yours would need like 4 square feet of cage space. For my cages I usually make them but you might not have the time or supplies. The cages I make are about 3/4 wire floor and 1/4 wood floor(for them to rest their feet on. I never let my rabbits out in the winter because they seem to run around a lot more in their cages when it is colder out. To keep it inside I would recommend making a stand on the floor under the cage that could hold a large plastic dish so the mess doesn't go everywhere.