2011 AirPort Extreme sill usable?

Just to make sure I understand your current networking components ...

... in addition to the new gateway you have both an 802.11n AirPort Extreme and an 802.11n AirPort Express? (Still would help if you can provide the model numbers for both, please.)

Is your goal to use both base stations to extend the wireless range of the gateway? Do you want the connections between all of the devices to be wireless or wired or some combination of both?

My goal is to use at least the AirPort Extreme to extend the wireless range, using a wired connection to the gateway.

Thanks for the updated information. When the connection between routers is wired we would have the basis for a roaming-style network. Each wireless router/access point used in a roaming network will broadcast their own Wi-Fi network, but since all of then will use the same network name, security type & password, wireless clients will only 'see' one network.

The important things to keep in mind with this type of network are the following:

• Connections between routers must be wired.
• Each base station used must have a unique base station name.
• Except for the 'main' base station, all of the other base stations must be reconfigured as bridges.
• Each base station must be configured to 'Create a wireless network." Do not use the 'extend a network' option.
• Each base station must broadcast a Wi-Fi network with the same network name (aka SSID), security type (WEP, WPA, or WPA2), and security password.

Let us know if you need any further assistance with getting this set up. Once completed, you can decide if you will still need to extend this new roaming network with the Express,