No problem. Ok, let's start by getting the AirPort Utility to "see" the TC properly.
Please try the following:
o Power-down the Netgear, TC, and MBA. Order is not critical.
o If currently connected by Ethernet, disconnect the TC from the Netgear.
o Perform a
"hard" reset on the TC.
o With power still off, reconnect the TC to the Netgear connecting an Ethernet cable between any of Netgear's available LAN ports and the WAN (circle-of-dots) port on the TC.
o Power-on the Netgear; wait at least 10-15 minutes.
o Plug-in the TC; wait at least 5-10 minutes.
o Power-on the MBA.
o From the MBA, run the AirPort Utility, and then, select the TC. (Note: The Netgear should NOT show up in the AirPort Utility list of available routers.) With your MBA connected wirelessly to the Netgear and the TC connected by Ethernet to the Netgear, the TC should show up in the AirPort Utility.
Let me know if the AirPort Utility can now "see" the TC.