AirPort Utility can't find Netgear router OR new AirPort Express

Question

Hello,
I couldn't find my situation fully addressed in older posts, so I'm posting one myself.
I am trying to EXTEND my current network with a newly purchased AirPort Express. My equipment is as follows:
Comcast modem connected via ethernet cable to...
Netgear Nighthawk AC1900 R7000 dual-band router
One three-year-old Mac Mini running Lion
One newer MacBook Pro running Mavericks
Two iPhone 4S, latest software updated as of Nov. 2014
Two-year-old iPad, latest software updated as of Nov. 2014
Newly purchased AirPort Express as of Nov. 2014
We have a large house with an office at the extreme end resulting in a week signal, so I need to extend my network. The Netgear router sends a strong signal otherwise, and ALL devices are working properly and are fully connected to the WIFI network.
So here is the problem:
I've tried many, many times to connect the APE using AP Utility with only two successful connections, but these connections were to "Join Existing Network" not to extend that network, but I selected this option as it seemed closest to what I want to do since "extension" of network was not an option. Then I see that I can edit the APE within AP Utility. I've done so, resetting the unit as a network extender, and the two times I tried this I sat waiting for five minutes for the thing to update only to get an error message. At this junction I could do nothing but remove the APE in AP Utility by "forgetting" it. No other options were available that I could see.
Now, the two times I've done the above, were two times within 20+ attempts to get AirPort Utility to even see the darn thing. I've tried placing the APE near the Netgear router, moderately close (other side of room) and even at the far end of the house, and neither the APE or the Netgear router were ever found in the AP Utility save the two incidences mentioned above. I've scoured the net, rechecked all connections and performed all troubleshooting procedures I can find to no avail. All I get is a flashing amber light and no connection
A: Why won't AirPort Utility find my Netgear Router?
B: Why won't AirPort utility find my AirPort Express?
C: Why, on the two occasions the AP Utility did find the APE, did it not give me the option anywhere to set it up as an EXTENDER to the current network?
D: Is there any other way to add the APE to my network as desired without using AP Utility? (I do have the Negear Genie app, but I don't see options for adding a device for network extension so far)
I'm at wits end. Can anyone help?
Oh, and I've tried using AP Utility on both Macs listed above with the same results.
Thanks for your help!

Answer 1

A: Why won't AirPort Utility find my Netgear Router?
AirPort Utility works only with an Apple router, as does the utility for a Netgear work only with a Netgear router.
B: Why won't AirPort utility find my AirPort Express?
Any of 3-4 common reasons. We'll have to work on troubleshooting that.
C: Why, on the two occasions the AP Utility did find the APE, did it not give me the option anywhere to set it up as an EXTENDER to the current network?
Apple designed the wireless "extend" feature on their routers to only work with other Apple routers.
D: Is there any other way to add the APE to my network as desired without using AP Utility?
No
Not sure how you want to proceed at this point. It might be possible to use the AirPort Express to extend the Netgear network if you connect it using a permanent, wired Ethernet cable connection back to the Netgear router.
If you cannot run the Ethernet cable, your best bet by far is to use another Netgear extender or repeater, which would likely be compatible with your Netgear router.