Kerry,
I like Graham's tighter crop. I think the pose is good and the expression is awesome. If it were my image, I would try to see if I could brighten her face/eye and/or darken her arms in front. I'm not sure the focal point/DOF is right for this though.
As far as ISO 6400, if you don't want auto to use it, I would think that is a programmable option in your camera - it is in my Canon 60D - mine is set to max 3200 ISO in auto. I have shot some photos at 6400 ISO looking for interesting grain, but I have been consistently disappointed in this regard - but also, i ramble on...