Apple has posted a firmware update for Bluetooth on its web site.
Here is the description of the update provided by Apple:
The Bluetooth Firmware Update 1.2 improves Bluetooth performance and reliability issues.
When the update package is downloaded, the Bluetooth Firmware Updater application will be launched. Follow the on screen directions to update your Bluetooth Firmware.
The Bluetooth Firmware Updater supports D-Link USB Adapters and Apple internal Bluetooth modules on the following CPUs: