Actually I think most of us would only suggest a good diet. At least that should be your base, and diet if the most effective.
Weight lifting would be much more benificial than cardio. It is plenty to get your metabolism out of the toilet. 1 lb of
muscle burns 3000% more calories than fat.
Don't get me wrong, if you are a complete couch potatoe, cardio will do you plenty of good. But eating 1000 calories less than you do now, is much easier than just adding 300 calories of "cardio".
You'll find plenty of good diets in the Diet/Nutrition forum. I'd start with some reading there.
Fudo