hi G.,
if you're already doing things like no-fried foods and lowfat dairy for the little one i suggest a few things:
1. watch what you eat in front of your child. she's picking up her eating habits from those around her and if that's mainly you then you want to make sure that you're eating well too. eating is such a social thing that if you've prepared a 'special' meal for you child while mom and dad chow down on fried chicken at dinner time then you're not going to have a very enthusiastic healthy-eater.
2. i'm a doctor of chinese medicine and find that many overweight people don't have complex carbs (whole grains) in their diet. try making a chicken soup with all the veggies she likes and add things like quinoa, millet, or buckwheat (buckwheat has a very strong flavor so go slow with this one until you know she likes it). i love making butternut squash soup with quinoa in a chicken broth base... very nutritious and delicious too.
3. cook her foods, even if just a little... not too much raw in the diet. fresh fruits are great, especially in the summer but try lightly cooking/ steaming veggies before offering them to her. raw food makes the stomach work harder to break it down because the stomach has to essentially 'cook' it (with more hydrochloric acid) before breaking it down and assimilating the nutrients. if she likes the crunch of a raw carrot try steaming it lightly so it retains its firmness but is warm. this will help her body use less effort to get the nutrients from her food. with this new efficiency in food-assimilation she'll eventually need less food and she'll have more energy for other things (no more food coma after lunch) and she'll certainly shed the pounds she doesn't need.
if you've tried everything under the sun then perhaps she needs her doctor to do a full medical work-up (checking thyroid function, possible allergies, etc)