untangle server.

hello,
i just found out about untangle.
Applications

here is the hard ware Requirements
Hardware Requirements - UntangleWiki

im thinking about building a cheap pc for it.
the idea is to plug the untangle server direct to the router using ethernet.
then my desktop downstairs plugs in to the back of the server.
hopefully i can stick in a wireless card in to the server so my desktop upstairs can connect to the internet with the filtering of the server.
probaly 2 nic cards and one wireless card.
do you think there will be any issues with wireless card?
or shall i just get a wireless router and plug it in to the one of the ethernet ports on the server?
just want to find out how much it would cost first.
just cheap as possible all parts from scan.
also i want is as quiet as possible.
thanks in advance

happy new year everyone lets hope its better than 2007:D