i dont know sprint.....but;
you say you have that card in your laptop, and you also mention a router.
so you have a router set up in the house, that the wireless card connects to right?
if thats the case, which is most likely is, then your wii should pick up the router as an access point, and be able to use the connection in the same way as the laptop would...
(so basically if you have a router, you are sorted )