I have the GA EP 43 ud3l motherboard and our boards uses the same audio driver. Gigabyte released a new Vista/Windows 7 driver on 08/10/09. Not sure if you have rev. 1.0 or rev. 1.1, but the driver is the same.
Find it here: Link Removed
Then scroll to the bottom of page and select your OS. Download from Asia, as it's the fastest speed.