First and this is VERY important.......live in a place that doesn't get below 35-45 degrees.
Second ride 3-4 times a week using a power meter. I recommend the iSport by ibike.
http://www.ibikesports.com/products_isport.html
This gadget will do more to improve your riding...made my thighs bigger in just 3 months.
What it does is show how much energy your using while riding. Slid my butt 1 inch forward and gained .5 mph. Showed getting in the drops saved 50 -80 watts for the same speed. Also the further back in the draft the less energy you use. One glance going uphill will relay if your in the best gear for climbing. Saving watts will get you riding farther.
Also has a fit test and three programs (FAT burn-Cardio-Strength) to use based on what you scored.
Body for Life could help you loose the weight which will translate to better power to weight for your bike.