Your saying that your computer is in the basement ? What are you doing listening to music or something that you want to have going on your computer and listen to it on the top floor of your house ?
The only thing I know of that will extend a wireless signasl is a repeater , but those are used for extending the wireless signal of a router.
Probably walking around listening to music or chatting on mumble with people. I briefly looked into a 2.4GHz wireless extender, but it seems like they are all designed to extend the signals for a wireless network, so I'm not sure if it would repeat my headset signal.