Unable to connect with TM-AC1900 router using NetGear Powerline 500 +WiFi (XWNB5201)

I am unable to to setup and connect my powerline system to my TM (T-Moble) ASUS TM-AC1900 router on my TimeWarner Roadrunner (Home/TV/Internet bundle system) - Cable modem is an Arris Touchstone Telephony Gateway TG1672/TW-0 modem. This modem is less than 2 months old. It replaced my older modem to keep the system up to releases. It also fixed a few nuances issues with our HiDef TV channels. Works perfectly. No Phone, Cable TV or Internet issues to date. My electrical system is regular 100Amp Home electrical on single homeowner property with 24 breaker power panel (a regular USA home electrical system). My powerline 500+WiFi  is on a dedicated 120v electrical circuit shared only by my computer and networking system that ties back to the main powerpanel. 

Problem:  I can't get the system to recognize each other's network and work together to have WiFi in the garage.

Questions:

1) Will this powerline system work with my router/modem/network system?

2) How can I get it to work?

Equipment;

Cable Modem - Arris Touchstone Telephony Gateway TG1672/TW-0 

Router -  ASUS TM-AC1900  (TM = supplied free by T-Moble to correct TMoble WiFi calling issues several months prior - no issues afterwards)

Powerline Adapter - NetGear Powerline 500 +WiFi (XWNB5201)

Bought the Powerline 500 +WiFi (XWNB5201) system at BestBuy yesterday after I was 100% assured by the manager at the local BestBuy that it would work flawlessly with my router and cable system.  Reason for purchase was that I have a long house and have to have the cable and router i.e., network system at one end of the house. I run hard line Cat5e cables to all of the bedroms and living room. No Cat5e to garage, dining area and kitchen (i kinow... hindsight suxors)  I have very poor WiFi (1 bar) at the other end of the house where the garage is located. Was told this was the answer to all my problems. Please help. 

Don't want to give up but if it wont work with my system I may have to. Prior to buying the Powerline I found nothing on the www or even here at least after the problem surfaced at least nothing in clear words what routers worked with the AC1900 or the TM-AC1900 before I bought / after buying.  I must have missed something somewhere because I don't think the right way to find out our equipment won't work correctly is to buy, install, and figure it out on our own. Especially if we don't want to be forced or held hostage into paying an additional $99 to BestBuy's Geek Squad to have them set it up for us or tell us after the fact that we need to take it back because it won't work for us. Despite of what the BestBuy manger and sales people tells us.

Pardon the upcoming but honest rant. That would mean no one should buy any product from NetGear because BestBuy's is going to take a little more away from us and NetGear.   Think you'll aggree that seems a bit out there but it's real and happening everyday .. hopefully there is a better way.  Would really appreciate any help.   Thanks ahead of time!