There are several similar wireless speakers in North America too.
If you don't mind wires, just take a 1/8 stereo extension lead (long enough to go from your computer to your stereo. Plug one end into your souncard outlet and the other into a "Y" splitter with 1/8" input and twin "RCA/phono" type outputs. These go into an "aux" auxilliary input on your stereo system. Just start out with low volumes on everything the first time you connect it.
Good Luck, JohnB