Best method of extending wifi signal with Nighthawk R7000

Hi all - we have a R7000 that is good but not good enough to extend to the further areas of the (new to us) house we have moved into.  However, we do have ethernet already wired in to most rooms.  If I wanted to run an ethernet cable from the R7000 to the further end of the house (part of the infrastructure is alreayd there, and then plug in an extender of some sort via ethernet, and ensuroing best compatability with my R7000, which would be the best solution? 

Ideally (mainly for the kids) it would be exactly the same network name (both 2.4 and 5ghz) and password so we have a seamless transition.

So rather than just boosting the wifi signal, I woant to use the ethernet cable to send to a new unit to provide additional wifi?  Thoughts?  Thanks