Since she likes cereal, why dont't you add some other food into the cereal. Not in large amount though coz her tastebud is currently exploring the different taste in food.
dont't keep feeding the same food everyday to her if you claimed that she is fussy. Give a variety of food mixed in plain cereal. Let it be, if she takes only 2-3 spoonful of the food you've prepared. But be sure to give more milk and perhaps baby biscuits in between. At least, you know that she will not go hungry.
Eg: mashed potato + cereal, mashed pumpkin + cereal, spinach + cereal, carrot + cereal.....you get what i mean yah!
I know how frustrating it could get, i had that from my second baby last time. But feeding lil bbies require patience.