I would love to know the same or even in the reverse direction, I've been pulling my hair out trying. lol. Connecting to a wifi hotspot (Alfa USB Wifi INSTEAD of using a 3G) and using the built-in wifi for clients. That way a downtown free wifi can be used to SSH tunnel through without having to subscribe to a 3G network with monthly rates.
Scenario:
Built-in Wifi<--- Karma clients
Alfa AWUS036H USB ---> *Public WiFi* (Providing internet to Built-in wifi clients) ---> SSH Persistent tunnel ---> My Home network via online ---> CPU w/BT5, tcpdump, sslstrip, etc. capturing
Dont really feel like leaving my tethered android or 3g modem w/battery pack out in the rough. lol. I can handle having a Jasper with a Alfa stolen but not the others. Just in case. ;)
---------
[uPDATED]
Forget my ignorance guys, I know my ifconfig commands, just need a refresher.
$ sudo iwlist wlan1 scan
$ sudo iwconfig wlan1 essid "bestcoffee"
$ sudo dhclient wlan1
??
then IP forward .... Any direction would be cool. :)