A.T.
My pediatrician said that my daughter only needed about 16 oz milk a day. As for fluids, I do let mine have about 4-5 oz of orange juice, and another thing you might try is diluted ice tea. There are a lot of herbal decaffeinated teas that are sweeter without any sugar. Try the berry ones. Just brew the tea and dilute with water and ice to taste if you don't have an ice tea maker.
As for carbs, my daughter loves pasta so that is her primary carb source. You could also try oatmeal or even cereal. Joe's O's are pretty low in suger.