Ah… ok. After a little research, that Internet Gateway icon is supposed to be there. It’s a UPnP network gateway on your network. It most likely isn’t your problem.
You said you mucked around with the IP address to connect to the Xbox. I think the biggest problem you have is that those icons in Network Connections aren’t profiles, they’re actual physical and logical network adapters. Change the TCP/IP settings for the Local Area Connection back to what they should be for your network and you should be ok. In theory.
If I’m totally offbase, let us know exactly what you see in Network Connections and what you get when you type “ipconfig /all” in a DOS prompt. (you might want to take put the MAC addresses and change the 3rd octet of the IP addresses)