To add in to Ironman's reply, gaining the muscle will help you shed more pounds by burning more calories. The more muscle you have, the more energy you use, and the more fat you burn. Building muscle burns fat, and lifting weights keeps burning calories for hours after your done lifting because the muscles stay hot, and calories are measure essentially in heat. Calories in scientific terms are measured in kcals, which has to do with how much heat one is producing.
I have actually read that cardio will burn calories only while one is exercising, whereas, as I said before, calories continue to burn for hors after one lifts. During the course of one of my classes, we were required to find out how many calories are burned during weightlifting, and with your bodyweight it is probably somewhere between 650 calories - 750 calories per hour, plus the additional calories that are burned even once your done lifting. To do that on an exercise bike, you would need to do that for 30-40 minutes at 15 mph, depending on your resistance. That's just for the initial calories burned, not for the extra calories. At 15 mph, one generally burns .097 calories per minute per pound biking, in case you wanted to figure it out yourself.