Watson:
Forget about the food and protein drinks, you need to ride a LOT more than you are currently, especially if you want to do well over 100 miles. The consistent accumulation of workouts is what delivers improved cycling performance. Let too much time lapse between workouts, and you will stay at the same level year after year and never improve.
You need to ride at least 3 times a week for at least an hour ideally. That's an absolute bare minumum, and that's just for recreational riding, not racing. Assuming a 15 mph average speed that's already 45 miles a week. You are going as low as 25 miles a week. Cycling is very time consuming. The only thing riding 25 miles a week will get you is frustrated when you don't have the stamina you need.
If you work 5 days a week, do a few hour rides during the week, possibly on a trainer after work, and ride for a few hours on your days off. Ideally, save one of your off days for a "long" ride where you go for 3-4 or more hours. If your knees and lower back are good, climb hills at least once a week also. The hills will help more than anything. Climb, climb, climb...
99.9% of all the pills and potions out there are worthless if you eat normally. The only ergogenic aids that really do work are illegal and are all dangerous to your health. Steroids, amphetamines, and EPO (Erythropoietin, a kidney hormone) will definitely improve performance, but the overall risks could hardly be considered worth it, especially with EPO.
Your current diet and the Cytomax/gels are fine. Do regular, consistent miles and climb if possible, and you find your overall fitness improve tremendously.
Good luck!!!