Help me with this diet plan, please?

I'm a cheerleader and we run a mile/take gymnastics once a week. I know I need to up my exercise. I'm 5'1, 147 pounds ( premenstrual bloat ), and would really like to lose about 20 pounds. For breakfast, I usually eat a bowl of Special K cereal, and 3 strips of turkey bacon. Lunch, Dinner, and snacks is where I usually mess up. For a snack, I consumed about 8 vanilla wafers, Nutella spread, and a glass of milk. ( Unhealthy, I know. ) Lunch, I usually eat a sandwich, but I don't think peanut butter and banana is that healthy.. even if the peanut butter is reduced fat ( containing more sugar nevertheless ). For dinner, I either plan on having a grilled chicken salad, grilled chicken sandwich, homemade pizza, chef boyardee pizza kit, or a lean cuisine. If anyone can help me improve my diet plan and give me some insight on how to lose it, I would really appreciate it. I have the rest of June and July before I would like to reach my goal. Thank you so much! :)