Thanks everybody. I tried to brighten up the right side of her face in camera raw, but I could only do so much before noise started to appear. It never occurred to me at the time to brighten up her right eye. When I took the shot I wasn't really thinking to much about lighting outside of getting a decent shutter speed, but I guess that's a noob error. I would also be interesting in learning more about reflecting light. Would a white sheet work as well? I really can't afford any more camera gear at the moment so anything on the cheap is good by me.
I did get a 11x14 print from york photo that came today, but it came out rather underexposed. However, they did say that I could send it back and adjust the exposure.
Btw, she's an English Spaniel. The breed is a little bit smaller then an American Cocker Spaniel. They are also somewhat less independent then their American cousin.