One other thing - when it comes to exercise, consider doing some weights as well as walking/running. This has the advantage that you will continue to burn fat long after you've finished your workout, unlike CV exercise which only burns fat while you're doing it. A combination of CV and weights is best.

It doesn't have to be anything to strenuous, just basic exercises that work the major muscle groups. Any good gym will be able to help you sort out a simple routine.