to answer your question, the easiest way to 'retouch' a photo is do the hard work up front. get your lighting set up, move stray objects that will distract from your subject, etc.
to retouch this shot would be tough. i am not sure what you are expecting to be done, or what your desired outcome would be. with that said, there are some VERY talented PS guys here who might be able to do something with it, but it would be a lot of work because of the lack of set up you started with.
BTW, your GF is very cute. I would bet that with good lighting and some minor makeup, she would need very little retouching.
It is really the "near perfect" shot that needs photoshop cs3 to tweak it. There is tons you can do to improve a poor shot prior to taking it - like lighting, pose, make up, etc. - none of which requires Photoshop.
Wow, if the photo wasn't funny enough already - Sheesh!!
here's what I'd do if I had PS on this computer:
Crop above those godawful stockings. Clear the mirror by cloning. Add a vignette to remove the blinds. Adjust the curves and contrast so it looks a bit more interesting. Maybe even do a b/w conversion.
in all sincerity, paul's first version is pretty darn good. so greg, if you are looking for a way to 'sell' you buying CS3, show her that one and promise her that by honing your photography skills you will be able to make her look even more beautiful than she already is! if she says no, drink a bunch of wine with her and ask again later!
My try. Don't really know how you want to make it look better.
Did a little sharpening, noise ninja, shadow/lgiht stuff, and framed. I'm not too good at photoshop yet but trying to learn as much as I can.
You should try photoshop element, it's cheaper. If you must have the big brother, I suggest that you buy the student version (cheaper).