Make muffins on Sunday and you'll be able to grab one to alternate with oatmeal all week. Just make sure they're legit muffins, not basically cupcakes. (Ie, ones with low sugar, incorporate fruit or nuts, use whole wheat flour, etc..)
I've done carrot-ginger-bran muffins, whole wheat zucchini, whole wheat lemon blueberry, and apple cinnamon oatmeal, and they're all around 200 calories (for the normal muffin size of a muffin tin, not the jumbo bakery size) and not too sweet.. perfect with a cup of tea. I happen to be a light breakfast person, so a 200 calorie breakfast is fine on most days, but if you want to up it, you could add a glass of milk and a piece of fruit, or whatever.