Shop: Newegg
$79.99 | ZyXEL GS1100-8HP Unmanaged 8-Port Gigabit PoE+ Switch
Newegg offers ZyXEL 8-PORT gigabit Switch $60 off w/ promo code 218CALVLUP37, limited offer.
$59.99 | TP-LINK TL-PA511KIT High-speed AV 500Mbps Powerline Adapter Starter Kit w/Gigabit Port
Newegg offers 500Mbps Powerline ethernet adapter with Gigabit port. Plug one of this into wall power outlet and ethernet from your router. Plug the other one on power outlet in downstairs and ethernet to the xbox, voila! Now you have a stable internet connection much stronger than wifi N.