Have you checked out Tricia's water dragon site? She gives alot of excellent advice on their care. Another thing to consider is: what was the dragon eating before you got her? You are right though that she needs a varied diet.
Here's the link to the diet specific page of her site:
The diet of Chinese water dragons (lizard, insect, cricket, meal worm, earthworm, pinkie, fuzzie, fish, vitamin, mineral, calcium)
She gives an example of what she feeds her dragons at the bottom, so I hope this helps. You should probably be feeding your dragon mice larger than pinkies, they don't have as much calcium, and she looks large enough to eat bigger ones. To vary the portion of her diet that is whole prey, you can offer chicks, mice, gerbils, fish (less fish than other whole prey though), and small lizards like anoles. Any of these things should follow the size guidelines given on Tricia's page. Good Luck!