I think you should actually see this as a great opportunity to grow both physically and mentally. I was an athlete in college and my parents also put me on a "3 day/meal plan," so I had to find ways to get additional food.
My first suggestion would be to buy some cheap plastic Tupperware (I know what it is like to be on a college budget). It doesn't need to be anything fancy, but this will come in handy when you visit the cafeteria/"buffet" style joint. Many cafeterias have a rule where you can get unlimited food, but you are unable to take it with you. The way to get around it is to simply get as much food as possible, put it in the Tupperware, and then put it in your book bag.
While at the "buffet", I would search for hard-boiled eggs in the morning, omelet stations, instant oatmeal, granola, and nuts. You can always take some extra with you. As for lunch and dinner, many of these "buffets" have a grill section where you can pick up your meats (grilled chicken, etc). Also, look in the salad section for cold cuts (turkey, ham, cheese) can all be used as sources of protein. You can mix it in with some veggies from the salad bar. Finally, be on the look out for fruits, (apples, bananas, and oranges).
Outside of your cafeteria, you can buy microwavable rice, tuna, sardines, other canned food, and mixed nuts at Walmart or any other local supermarket. You can get your brown rice for regular meals and white rice for post-workout. Also, those instant oatmeal packets that you took from the cafeteria can also be popped in the microwave. Of course, don't forget to get a small blender or blender bottle in order to mix in your protein, which you can get in bulk to save money.
My final piece of advice is to have fun, but do not get carried away. This can be particularly hard during your first two semester. Nothing will kill your progress like drinking everyday from Wednesday to Sunday on a weekly basis. I hope that helps.