In order to lose weight you need to incorporate both strength moves and cardio. You need to get your heart rate really pumping for at least 30 minutes a day, every day.
Walking on the treadmill isn't the best exercise for weight loss. It's good at first to kick off your fitness routine but after a few weeks you will need something more. Try movements which use the whole body - lunges with a bicep curl incorporated, jump squats, skipping, step ups with a bicep curl. These are the best movements for weight loss as they include both strength and cardio.
Good luck and check out my blog for my own experiences as well as good tips for weight loss and fitness!