You'll have problems setting up Wifi at console because iwconfig doesn't like passphrase-based encryption; it could be done using unsecured wireless or a good old-fashioned key, but it'll be hassle.

(Edit: if it's set up and just needs to be enabled, then you might just try an "iwconfig wlan0 up", or if it's been disabled by something like WiFi switcher unloading the kernel mods, try "modprobe wl12xx" beforehand.)

BackupMenu is probably the better call assuming your phone is functional enough to use it, and it'll be easier to get your existing Vodafone connection online at console than to configure wireless.

So, from your xterm:

gconftool-2 --set --type list --list-type string /system/osso/connectivity/network_type/auto_connect[*]

will change your Internet connection type from "always ask" to "connect automatically" and, if you needed to manually put the phone into 3G mode,

run-standalone.sh dbus-send --system --type=method_call --dest=com.nokia.phone.net /com/nokia/phone/net Phone.Net.set_selected_radio_access_technology byte:0

should take care of that. Provided your Vodafone 3G connection was previously configured, that will get you 3G mode and connect automatically, then you should be able to install BackupMenu as per mrsellout's instructions.

See how far that gets you; BM offers USB networking as well as mass storage, which might make the idea of setting up WiFi redundant.