Believe it or not, her diet is actually pretty darn good! Beans are one of the best vegetarian sources of protein, so if that's one of her favorites, she's probably doing more than fine there. As for the veggies, I've read that kids can get most of the same nutrients from fruit. Since it doesn't look like she eats a wide variety of fruits, you might try getting sneaky on her. Veggie puree was my best friend for awhile...you can try spreading it on toast, mixing it with her cheese spread, mixing it in with her beans and toast or potato, spreading it on her waffle, or using it as a "sauce" for homemade pizza (toast, veggie puree, and melted cheese on top). Oh, and it can be hidden in yogurt or smoothies too. Even if you think "ick" at the thought of mixing veggies with some stuff, like fruit yogurt, give it a try...you might be surprised what you can get away with! Even if you can't get veggies into her, it doesn't look to me like she needs a supplement.
It sounds like you have a great attitude toward mealtime!