I was going to suggest the same thing as bicyclette. Eat something hearty for lunch and eat a pb sandwich or something similar for dinner that doesn't have to be refrigerated.

I see you have a whole foods in San Antonio, have you been there? Some items there are a little pricey, but maybe 3 times a week you could have a premade salad with some meat (you could buy these ahead on the weekend)? You might check to see if they have any instant cereals for the morning like instant quinoa, kashi, oatmeal, etc. Those would provide more fiber than bagels or poptarts and should keep you feeling better satiated.

Instead of chips and a cookie at lunch, how about some dried fruit, trail mix or nuts?