from your screenshot, nameserver is most probably wrong, and default gateway should be smthg like 192.168.1.254, and not 'dsl'
Some routers would indeed resolve like this.
route -n
would show the IP.
Either way, I could not see nameserver showing in screenshot.
.
3. in aterm, type: sudo ifconfig eth0 essid YOURESSID key YOURKEY
Those are rather options of iwconfig than of ifconfig.
kurch has not been clearly stating in what way they would connect, but given the ifname I'd reckon it's ethernet.
EDIT: Oops, now I can see what maro meant about "having to scroll around", hadn't occured to me...
Nevertheless, I think '192.168.1.1' would be most common if one uses nameserver on a router.