dbkluck is correct about the 169.254 ip - you are not getting an ip.
when you typed in ifdown then ifup was there any error at all?
I presume the default on the nic is DHCP as it is on a router. This has been the case in my experience.
Have you reboot the system for good measure???
If not then do so and then see if ifconfig has a real ip from the router.
You can always change the config of the nic in X off the start menu [which is the easiest for a newbie] I recommend this in your case. If you want to change the config of your router you can browse to you gateway ip in a browser, login and change to the relevant configuration. If you need more help on the router config you can just call their tech support and they will walk you thru it on the phone.