Airport extreme to make wireless connection for Sonic Wall

Wondering if the Airport extreme can be an access point to give us wifi since our access point now is terrible.

Yes it can. The AirPort Extreme would need to be connected to the SonicWALL by Ethernet, and then, reconfigured as a bridge.

There are a number of SonicWALL devices. Is the one used at your office a wired-only or wireless model?l

Ok, then you would connect a single Ethernet cable between one of the available Ethernet ports on the SonicWALL and the WAN (circle of dots) port on the AirPort Extreme.

Temporarily connect a PC with another Ethernet cable to one of the LAN ports on the Extreme, and then, access it with the AirPort Utility.

In the AirPort Utility, you will perform the following steps to reconfigure the Extreme as a Wireless Access Point:

• AirPort Utility > Select the Extreme > Manual Setup > AirPort
• On the Base Station tab, enter a name for the base station in the AirPort Extreme Name field. I would also recommend that you create an Administrator password by entering a password in both the AirPort Extreme Password and Verify Password fields.
• On the Wireless tab, select Create a wireless network for Wireless Mode. On this same tab fill in all the other fields as per your networking requirements.
• Select the Internet icon
• Click on the Internet Connection tab to select it.
• Change Connection Sharing to: Off (Bridge Mode)
• Click on the Update button to write the new information to the base station and allow it time to restart/reinitialize.