Okay, it's not as important as needing a doctor or anything, but this is important to me. I'm printing something either tonight or in the morning. So I need to know how to do this within 12 hours. I made a test-print of it but the colors were too green and too dark.

I think I know the basic idea of color profiles, and I know how to assign them to monitors/printers/etc., but I've never been able to understand exactly what to do to get the colors to match in-between devices. Do I have to assign both devices the same profile? How do I make sure I'm using the best profile for my monitor? Is there a best? If I'm using two different profiles for the monitor and printer, then how do I go about finding the best profile for my printer? Do color profiles change with each image or over time?

Seriously, this is an issue that has been confusing me for a while. If you can help, please tell me everything you can on the subject. I'm very busy so I'll check back later. Thanks for helping.

(I'm posting this in both GimpTalk and GimpChat to get as many answers as I can. The other post is here:)
http://gimptalk.com/forum/viewtopic.php?f=12&t=50553

EDIT: Also, can my colors be corrected too much? If my OS and GIMP both uses a color profile; do they supplement each other, thus over-correcting the colors?

EDIT2: For example, this is approximate to what happens.

Have you tried the CYMKTool?
You can open an image made in Gimp, and convert it to CYMK with any profile.
http://libregraphicsworld.org/news.php?readmore=487

I'm still completely lost as how to color profiles should be set up; but thanks, I'll look into it.

It's no longer an urgency, but I do still want some help understanding this.

Thanks to Rod for at least trying.