Cardio exercises - walking, treadmill, jogging, stair stepper, etc. - will give your metabolism a good boost.
Do you take any vitamin supplements? Dr. Atkins recommends, in addition to a good multi-vitamin (without iron) Chromium, Essential Oils, and L-Carnitine and CoQ10 to give your metabolism a boost. I take them all and it seems to be working -- and I do cardio a minimum of 30 mins a day, 5 days a week.