First, realize that the prints can never look *exactly* like the monitor, because ink on paper doesn't behave the same as light emanating from a screen (for example, the appearance of the print depends on the lighting conditions you're viewing it under).
Second, there are entire books written on color management, and giving you a really good short answer here may not be possible. But, to try to point out a few things...
To get a good match, you need to calibrate your monitor. If your monitor isn't calibrated, it may be nowhere near any standard.
You also need a decent profile for your paper and ink combination. You can usually get them from the paper manufacturer. If you use Canon papers, you can get them from Canon. If you're using a no-name paper that doesn't provide profiles or tell you what canned Canon profile to use, don't expect to get decent results. If you're *really* picky (though you're unlikely to be there yet), you can buy custom profiles for your paper/ink/printer combination.
To get decent-looking prints, you need to get all the print settings exactly right. Ian Lyons' web site has a great tutorial on the right Photoshop print settings:http://www.computer-darkroom.com/ps9_print/ps9_print_1.htm
(There's a lot of other great info on his web site, too.)
This is an overview of the issues, though you need to search the site above, and this site, and these forums, to get a good understanding of the issues involved and really do it all right.
Lastly, "canon doesn't support photoshop" must mean that the tech guy you talked to just doesn't want to deal with photoshop issues, not that canon printers don't work well with photoshop. He/she probably realized that they couldn't deal with the full complexities of the problem in a phone call.