Installation

Hi all
Been using the muscled Pfsense for a couple of years and now i need a light OS to run as wireless client .This is where monowall comes handy, but i have a few problems.
I want to use a mini-itx motherboard (commel LV-602) it only has one wired NIC and e will add a Wireless card, i'll have only two network cards .
In this scenario how do i setup my monowall to have it runnig as a  wireless client (I dont need help to setup the wireless connection)
I need help to know which card will be better to set as the wan ,what services must i run for the trafic to pass from LAN to WAN & Wan to LAN .

My network diagram:

Pfsense[DHCP,captiveportal,PPTP]  10.6.30.254/24
                             |
                             |
          Ikaruos[access point]   10.6.30.250/24
                             /
                             \
                             /
                             \                     
                         Wireless Card (LAN or WAN ??)
                     [M0n0wall]
                          Wired card (LAN or WAN ??)
                              |
                     Computer(192.168.1.1)