How to edit when your tools are dull

[MotorToad]

So I took a shot of my friend's dog when I took it to the park this afternoon. When I I loaded the pic up I thought it was just the thing, just like I saw it when I was there. I've been told that it's over exposed but I'm not so sure. Basically, I'm limited to editing pics on a laptop that makes my 30D look positively state-of-the-art, and apparent exposure changes drastically with just a few degrees of screen angle. I don't much trust the camera's screen, either, so what's to do?

I've recently been pretty impressed with myself because picasa's "I feel lucky" button only makes tiny changes to my pics.