Composter Indigestion

My composter has indigestion. I try to feed it, but it just isn't very hungry! The decomposition rate really hasn't been very impressive, and my compost heap just looks like a mound of disgusting, wilted vegetables. There are a couple reasons for this. 1) Its been cold outside. There really hasn't been much insect activity at all until the last two weeks or so when it began to warm up. For a while, I might as well have been storing my organic waste in the refrigerator. During this time even a larger composter with a bigger community of decomposers would probably slow its rate of decomposition down, because many of the bugs simply wouldn't be active. 2) My composter is on a balcony several floors from the ground. The rate of immigration to my composter has not been as high as I anticipated. I would like to supplement my composter with worms, which would speed the process up, but I haven't found a good source yet. I tried digging, but I didn't have much luck and I didn't want to do too much damage to the esplanade. Furthermore, there is a lot of mold present in the composter. I fear that if I were to dump a colony of worms into it, they might be at risk of some sort of infection. I refuse to have worms shipped to me, so the hunt for local worms will wear on. When I move to my new apartment in May, I will be on the ground floor. I expect the composter to be more successful during the summer and on the ground.