hi muko...
earlier, i listed a bunch of options, e.g. free converters, and a plugin that works with photoshop CS. didn't get any response from you.
i have two more suggestions.
1) upgrade your photoshop CS2
2) this method is troublesome, but free. download the adobe dng converter (look for it on the adobe website), then convert your 5D raw files to dng. you should then be able to use them in photoshop CS. i haven't tried it, but my friend has been doing that with his d70s files.
good luck.