Dun1 Loc: Atlanta, GA

First of all congratulations on your iMac purchase. I don't think short of installing boot camp, or Paralells on your Mac that will allow you to run you Mac in the Windows mode, there is a solution. The first thing you must decide is if you wish to do that since. I don't know any true diehard Mac users, me included that want any Windows software or programs on my Macs. The next thing you have to overcome or decided is if you the plug ins you have from Topaz work on a Mac OS. Most of the software is specific to either Mac operating systems, or Windows including most of plugs-ins and additions. I use cringe every time I go to a Windows machine to work on images. You may have to purchase the version of CS5 specific for a Mac. By the way the latest and greatest version of CS, CS6 is scheduled to roll out in Spring of 2012, and unless you have at least some version of CS5 at the current time you will not be able to leapfrog from say CS4 etc to CS6 without first purchasing CS 5
I am the same junction, I am planning on upgrading or purchasing a new iMac, and my greatest fear is moving the software and plug ins I have and use to the new machine.
One other thing you might look at or consider is the Migration software that is available on the iMac. Too see if there are any options that might assist you in the move,

RMM Loc: Suburban New York

Migration Assistant is for moving from one Mac to another. It won't help with Windows software.

Before you do your upgrade from one Mac to another, check with Adobe. For one thing, you will have to reactivate your Adobe software, which is linked to the old Mac. You can activate on two systems, e.g., your desktop and your laptop (for YOUR use, not so that both copies can be used by different people). If you've done this, migrating will result in a third activation. You should deactivate on your old system before trying to activate on your new one. If you run into a problem, you'll have to call Adobe for assistance.

If you have the full Creative Suite, you could run into some other problems. I had to uninstall/reinstall CS5 on a client's new system because Photoshop and Illustrator worked OK, but InDesign crashed repeatedly. Everything else migrated without a hitch.