2009 Mac Pro Bluetooth - think I need a dongle

I have just taken delivery of a Magic Trackpad (I like the way it works with Logic Studio), but the BT connection with my 2009 Mac Pro is very intermittent. I can't seem to maintain a connection for more than about 10 minutes.
This is the first USB peripheral I have used with the Mac Pro (I am using the wired keyboard & a Logitech Mouse) so was blisfully unaware of the often reported Bluetooth problems with these machines.
The computer is under my desk, and given the content of all the threads I have now read about these issues, I am not sure whether to even bother calling Applecare. I am thinking I might just order a Bluetooth dongle and have done with it.
Can anybody recommend a good one that is likely to work well with the Mac Pro? I am in the UK.
If anybody has any helpful suggestions that would mean that I can avoid having to get an external dongle, please do let me know, however I am aware that this topic has been covered before so I don't expect people to repeat themselves unless they want too!

Great, thanks for the suggestion.

I have just gone and got one of those little Belkin USB BT receivers. It's really tiny, so it neatly plugs into the USB socket on the side of the keyboard, and you can't see it. Plus, it's right next to the trackpad so the reception is good.

I've had to re-pair the trackpad, but it seems to be working really nicely, so far.
It's a real shame that you have to spend your own money to get another BT adapter for your expensive computer, but I would recommend this solution to anyone with the same issue.

I was ready to have to get an extension cable as well, but thought I would give it a try on it's own first.