Mac problem in Windows Network

Hello, I am in need of rescue here. We have an network of about 70 PCs, two of them are MACIntosh. I have set up a wireless access point that connects (via wireless NIC) 7 of the PCs including one of the MACs.
My problem is all my IBM PCs are connected fine, to the server, network drives, shared printers, Internet, no problems. The MAC, however, can only surf Internet, but no connection to the server, can't see the network drives, can't see the shared printers.

The other big problem is that I am MAC illiterate. Please help advise. I really need help on this one. Please.

Which OS on your Mac's? Looks like you'll need to play with the Mac's AirPort settings....

Hi, thank you for your reply.

MY os is OS X. Can you specify for me what are the exact settings to configure? because I am really lost at this.
Please, I need any help I can get.