Your best bet is to get a wirless router.
All your connection options are listed here:
hello, i want to get wifi for my wii but, i cant use the LAN adapter because i dont have an ethernet port on my modem,and i have a Mac for a computer
does anyone know of something i could get???
Going wireless is cheap and productive, setup is also easy, just go wireless, can't go wrong with that.
thanks guys ill try that!