Ad hoc network help wireless internet connection

ok people this is what i need to do.

We have 2 computers and xbox 360

one pc conects wirelessly to a router next door as we share the internet and gets an excellent signal.

Now we want to make an adhoc network between that pc and another pc in the bedroom allowing file sharing and internet sharing.

Is this possible at all ? the main pc does have 2 wifi cards but i cant get them to work right?

also can the xbox 360 join the adhoc network or could we also plug the xbox 360 through thernet as its right next to the main pc

PEOPLE PLEASE HELP

Yep.. It will work.. Have a look on this Internet Connection Sharing Tutorial.. The ICS host can connect to wired or wireless network to share Internet connection.