Congratulations on your decision to make this a healthy year! As you can see in my signature, this is also my goal for 2007. I have about 25lbs to lose, and it's disappearing – slowly but surely.
Advice? Well, what I know so far is that exercise is a great mood booster - so keep up those walks - they will work wonders on a positive mental state, which is just as beneficial as any fitness gains.
Best wishes on your journey.