Here's the link: http://www.stuffedcow.net/macbook_audio
To install it, extract the archive to your desktop (it's already in a folder) or anywhere convenient. Then, open Device Manager (Start > My Computer (right-click) > Properties > Hardware tab > Device Manager.) Expand "Sound, video, and game controllers" and double-click "Cirrus Logic HD Audio". When the Properties dialog appears, click the "Update Driver..." button. Choose these responses I have outlined for you here:
- No, not this time
- Install from a list or specific location (Advanced)
- Don't search. I will choose the driver to install.
- Have Disk...