you should try playing around with it..
It's horribly overexposed. Trying to raise brightness and contrast blows out that wall behind them and makes the grass too bright and pixelates the whole photo. You can't just *fix* the photo, you need to take it reasonably first.
I'd suggest re-shooting with proper exposure.
The kid on the right especially, his skin is still flat and brownish in the edit. But you can see the difference between the original. You can see the levels breaking from the brightness. Maybe dodging on photoshop would be better, but this was done on Photobucket so bear with me.
Edit: