Sorry, but those are the drivers for the WiFi card, not the Bluetooth card.
I also have a Truemobile 300 Bluetooth card and have been looking for the drivers. It would appear that there are none at this time, but they are due out by the end of August.
However, that is only what I have read on forums and not a "true" response from Dell. So,
There is some additional information if you follow this
link to the officail Dell support forums.