You can get a wireless sensor bar, which needs batteries or a wall-wart. It doesn't need to be within any sort of range as it's just a pair of IR LEDs to give the Wii Remote a reference point. The limiter may be the Bluetooth in the Wii Remotes, as they are only good for about 30 feet. Your play area may only be 25 feet away though, so you might be okay.
I will make a suggestion and if this is not allowed mods please remove my post
I have my wii in the next room and it works great the only thing I had to do to make it more enjoyable was to mod the wii for a USB harddrive as having to run back and fourth to change games.