Having the fonera as a second access point can be a good thing if you have it far away from your main wifi router, but doing that in the standard way fonera allows you means cabling.
However the freewlan.info addons allow you to connect your fonera to the Internet via wifi (sounds ideal to use the fonera as a repeater, doesn't it?). This however seens a bit tricky, so I'm going to write down how I managed to do it, or at least part of it.
The setup is done via Advanced -> Internet Connection, there we must choose WLAN (QRM) as the wanted mode and then fill in the needed data for this connection.
I tried with a WEP connection and had some trouble, the config you type there will be passed to wpa_supplicant and quotes are not allowed, so had to enter the value in hexa instead of using the string mode. After that, things should be working, but I still could not get from the fonera to my router, the problem was that I had set the Authentication Mode as Auto Select, setting it as Open solved the problem.
There seem to be some problems with this fon firmware, probably with the madwifi being too old and buggy and I see things like a reflection of the WPA2 network on another channel and stating it is WEP based, ... So... this kind of works, but I still prefer my own OpenWrt based stable firmwares, the guys at OpenWrt rock ;-)
BTW: as I was playing with the wifi and until I got this setup to "work", the only way to access the fonera was through the ethernet, which I had connected directly to my laptop, at that time the fonera was picking up address 169.254.255.1 and I was accessing it using "ssh -L 8080:localhost:80 email@example.com" so that I could access the web interface on my laptop at localhost:8080.