Did you ever get your picture done? If you have Photoshop, there are many ways to isolate the background. You can cut a path on the foreground subject, or use the Image/Color Range to create a mask of the background. Once you have a mask created, make a new adjustment layer, and use either curves, channel mixer, color balance, or selective color (selective color on the neutrals would probably be the easiest). If you've never used Photoshop, it can get prretty complicated.
If you e-mail the pic to me, I can probably whip it out for you pretty quick.