I'm not trying to dishearten you, but fruit juice is basically just water and sugar. Fructose, the naturally occurring sugar in fruit juice, is handled exactly the same way as glucose, commonly found in the form of granulated sugar, corn syrup, and honey.
We buy greek yogurt (Dannon "Oikos" brand or Chobani), which is high in protein and low in sugar. Be aware that some greek yogurt is high in fat (both of the brands listed have 0% fat).
I don't unfortunately know of any organic greek brands, but I bet if you visited a Whole Foods or maybe even a Trader Joe's, you could find some.
A suggestion that might work is to buy low-sugar organic brand (maybe Stoneyfields? That's the only one I see at our story that is organic). Then, add no-sugar added applesauce for sweetener or some pureed baby food fruit to flavor it. Since it's fruit you're adding, you getting the extra fiber, vitamins & nutrients in the fruit itself, plus the yogurt. We buy Motts and Muscleman no-sugar added applesauce cups--they are yummy, come in a variety of flavors (peach/mango, blueberry, strawberry, pomegranate, etc.). The flavors are light, because the other fruit is generally secondary to the primary ingredient of apples.
You can make your own organic yogurt really easily:
http://ourlifesimplified.com/kitchen/all-recipes/homemade...
Just buy an organic starter (ie, 1 cup of organic yogurt from the store), plus the organic milk of your choice.