Here's a suggestion - try this little tool -
http://css-color-replace.orca-multimedia.de/You will need to have your style sheet on your local computer first. Don't forget to save a copy of the orig, BEfore changing, in case you need to roll back. Then find it and upload it. Play with changing your colors - you will not see live changes, will need to upload the changed sheet to site and see what needs to change.
Don't forget to clear your cache on the admin on the cart, AND on your browser.
Give it a try, it might get you what you want.