First off: really beautiful work. Your handling of the lighting is wonderful, and the integration of the figure with the other elements is really solid, not just a lame copy/paste into a background. The darkness from the rest of the image intrudes into her hair and clothing really wonderfully, and makes for a cohesive look. The push and pull of temperature and the complimentary greens and reds really underscores the vibrancy of both these colors.
My major critique is that it almost looks like a flat black background, but then I realized it wasn't. I thought perhaps I had something on my monitor, but noticed it changed position as I scrolled. Even after playing around with the contrast settings on my screen, I can't quite make out whatever texture is supposed to be behind there, mostly to the left it looks like. I get the impression that it's supposed to be stone, but it's very difficult to read and if I hadn't looked closer, has the potential to just look like noise in the image.