How can I lose 3 lbs of muscle weight?

Hi, I started running and I gained 3 lbs of muscle mass. I want to lose it, so I stopped running, and started to eat a little bit less. However, It has been 2 days and I still don't see any weight loss, I haven't gained any weight though, so I suppose that is good. Anyway, the reason I started running was to maintain my weight but instead I GAINED!!! argh! I also am not looking for muscle gain at all, in fact I need to turn any form of muscle that I have into fat. I need more fat percentage on my body, but I DON'T want to gain weight! How many calories should I eat per day to lose 3 lbs of MUSCLE WEIGHT. I don't run anymore, until I have lost these 3 lbs, then maybe I will start to run a little bit more lightly. Please help me someone, I am desperate to lose 3 lbs! :(