Just in case you missed my response on the other thread:
That wasn't protected content when I looked at it. I don't have membership either - didn't realize it was necessary. Fortunately, the process is very straightforward.
1. Download the Mac OS X 10.4.8 update from Apple's support site.
2. Download
Pacifist (used for extracting files from the package).
3. Mount the OS X 10.4.8 update DMG file.
4. Open Pacifist
5. Drag the .pkg file from the DMG file and drop it onto the Pacifist window.
6. Click the triangle next to System, go to Library, go to Extensions and then drag and drop IO80211Family.kext to your desktop
7. Open Macintosh HD and browse to System -> Library -> Extensions.
8. Drag and drop the IO80211Family.kext file from your desktop into the Extensions folder.
9. You will get an error message, be sure to click on 'Authenticate'. You'll be prompted for your password and then the file will replace the existing.
Reboot your Mac and you'll find that you're now back on the old driver. To confirm this, run Software Updates and you'll notice that it wants to install the 2007-001 update (don't do it!).