WAN Client of an AP - LAN as AP

[Summer]

With two usb wireless antennas would it be possible that : :D

1. one device: act at the same time as wireless Client of an existing extenale SSID and use this as WAN to internet access
2. second usb: create an internal SSID which act as LAN that allow her clients to access internet trought the WAN?

If yes could you suggest best hardware solution?
I've tried a Microtik 951G but got only one wireless interface, and will pfsense run on this?