Part of the problem is some of the food you're eating isn't really nutrient rich. For some other ideas, check this site: http://www.whfoods.com/foodstoc.php

I buy all my food in the bulk section, but I don't mind spending a half hour in the kitchen getting dinner ready. If you've got a co-op somewhere close, that's a good place to find things like quinoa and fresh whole wheat pasta. Local butcher stores are a good place to get quality meat at a decent price. And since you have a bike, it's easy to shop around .