You've gotten some good advice
Definitely change the white balance, probably to Incandescent Light or Tungsten. You might still however get some reddish tones reflecting on her from the backdrop, but it should be a little better. If can do a custom WB on your camera, that would be an even better option.
To allow more light in you can increase the aperture (smaller values are actually bigger as far as aperture goes -- f/2.9 is larger than f/8). Wider apertures (smaller values) make for shallower depths of field, meaning that your focal point will be sharp but with more noticeable blur around the main focus. So if you do this, just make sure you're focusing in on her face, and not her entire body, since it's most important to keep the eyes in sharp focus.
If all else fails, I'm sure there are plenty of photoshoppers on this board (me included
) who would love to play around with a few images and see what we can come up with!