swimming will help you lose weight all around your body. Also, you sweat much more when you are swimming than when you are running. Just to let you know. =)
I recommend a treadmill. I am rather large chested and despise running myself and a treadmill is a great way to reduce impact. Also an Elliptical machine goes through the motions of running without having to pick up your feet, also making it low impact. A cross-trainer can also help and has a benefit of working on specific muscle groups in your legs. If those ideas are too close to running, try a bike. They are easy and fun and burn 317 calories an hour if done at a decent pace. (Running may range from 330 to 360)
Strength training, makes you sweat hours after you have left the gym-increases your metabolism too..When on a treadmill use the incline as high as you can (I do a 6.0 incline at a pace of 3.3-Good luck!