the cable is about 12' long and needs to be centered either above or below your TV. All the "wand" (I'm assuming you're referring to the IR bar) is emit an IR signal that the Wii remotes detect and use to calibrate position. From what I've read, it is pretty easy to make one yourself, if you are so inclined.
As far as extending it is concerned, not possible without wire cutters, it has a proprietary connection. I wouldn't be surprised to see someone like Pelican offer an after market version with a longer wire. You could also Google for "homemade wii sensor bar" to see about building your own.