I think the lack of a heater could be why your betta is inactive. I had to keep my betta in a smaller tank temporarily for a while and the heater in it wasn't very good. He became vrey lethargic very quickly. Back to his old self once in his normal, nicely heated tank though.
Don't know where you are in the world or what your climate is, but if its winter where you are you should get him a heater quick-smart. (and a new tank/container). Try a tank/container about 2.5 gallons or above. Like others said, you can use tupperware and things if you can't afford a new tank right now. there's some pretty cheap plastic ones around, including in Wal-Mart I believe.
We don't get Wardleys where I live so I can't comment on that.