Need help with Netgear. Self-assigned IP

Hello, everyone.
I'm Ty and I cannot connect to the internet.
I'm am on the internet through a cord connected to Netgear.
I have had this problem twice before. The first time, I messed around with system prefrences and it worked. Second Time, I couldn't get internet, self-assigned IP, Plugged my laptop into Netgear, it got the Ip, had internet.
Now, today is the day after my second attempt, and now, even though it's plugged into Netgear, it won't pick up the IP. I can only get internet if my computer is plugged in. Any one know how to save the IP or something. At the moment I have my network settings open and for Airport it says' Self assigned IP' and for Ethernet it says 'Connected'. For bluetooth and Firewire, it says not connected.
So, anyway I cannot get internet to work wirelessly.
My step brother and step-sister are on the internet, and it works fine for them.
I have leopard
I can has help please?

 

No, I have a laptop, I don't have a wired connect, except the cord that comes straight from netgear. After fiddling around with it, I got an IP adress, but it still won't let me go onto the internet. Here's a screenshot. Help, please.