Fios router/wifi house question

[Lilmishabear]

Help!  I have an odd setup with my Fios Internet/Cable and wondered if anyone can offer a suggestion?  Here's my setup:

From the outside, my main router is the FIOS-G1100.  It's at one end of my house(ranch style).

Connected to that, about 30 feet away, is the ActionTec WCB 6200Q extender.  It appears to be connected via a coaxial cable.  

What's happening is my wifi is just horrible.  Where the main router is located, seems to get the best wifi connection.  But, I think the extender is supposed to be the main wifi connection?  Honestly not sure.

I then have a long hallway and the wifi signal starts dying the further you go away from the extender.  I bought a Linksys extender and have it plugged into an outlet in the hallway, but it honestly doesn't work well and if you got into any of the rooms off the halway, the connection dies completely.

Would a 'mesh' system work better for me(eero or nest)?  And if so, how do I set it up?  Do I ditch the G1100 and start over?  Or connect it to the WCB6200Q?

I know there's a good way to do this, but I don't know how.  Can someone please give me advice?

Thanks!

[appDev]

How fast is your connection? (gigabit or lower)?

First of all, are you sure the extender is working ok? if nothing else, right next to the extender should give you GREAT wi-fi. Or is it that the signal is great, but not the speed.

First, id focus on the signal being available.

Second, if you do not have Fios TV, using your own router is relatively easy. certainly doable with TV as well, just more steps. I am in the process right now (with TV), so happy to answer questions. I just proceed at a snail's pace..