Couple of suggestions:
1. Plan your daily calories (maybe start at 1500 cal/day)
2. Count your calories
3. Ration your calories like money...when you run out...that's IT! YOUR OUT!
4. Outdoor exercise is good...but you should also have indoor exercises avail (rent/buy a video or go on craigslist and buy a cheap treadmill if you have space).
5. Hang out in the calorie counter's section of this site...you'll get many tips and can even post your daily menu and exercise (I do...see the link in my siggy)
6. LAST...but certainly not LEAST...SLOWWWWWWWWW DOWWWWN!!! This is NOT going to happen overnight...it will take planning, persistence, readjusting...more planning...a slip up here and there...then again more persistance...catch my drift? Good news is that YOU CAN do it...I did...lost over 50 lbs in a little over 6 months...NOW GO GET EM!