Very short notice to set up a system, in fact very short notice even just to price and order a few workstations and have them up and running by christmas never mind set up a system.
On a different note, when you say wireless I would immediately think Apple Airport Extreme. Around 100 quid for 1 unit, easy to set up plus has 4 cat5 sockets and a usb socket. So with the usb you can plug a printer into it to serve as a network printer (I havent done this but it can be done). You can use it as a mini hub for 4 machines if you dont want them to be wireless and it is easy to set the password and security features on. I have found them to have an excellent range, if you use more than one they can be set up as repeaters to widen a wireless network. They are by miles better than the expensive cisco stuff C2k force you to buy for their system.
What are they basically going to be using this network for and exactly who came up with this idea and timescale. Round here it can take a couple of weeks just to get the boss to sign off on a requisition order never mind the time it takes to decide what spec of machines are required and the costing of machines from suppliers.