Ubuntu is Linux for dummies hehe. You can get a livecd that runs the OS without needing to be installed on a hard drive. You could use it to create an access point to play your Wii with.
Did you install the new drivers from the Asus site? I went to the driver page for your motherboard (slot am2) and there are Wireless drivers for Vista 64 released in November. It might reenable the access point function.
Honestly this is all a hack. You should use a real access point for best results.