I am on FIOS gigabit router; is it possible use Nighthawk R7800 as AC point and EX7000 as extender

I switch to verizon Fios from Cox Cable.  with cox i used my own router the nighthawk R7800 and got good wifi everywhere in my house.  Now on Verizon using their gigabyte router, very weak wifi.  Asking if I can use the R7800 in access point mode and further extend my wifi by hooking my EX7000 as a range extender to the R7800.  If this can be done could use some good instructions on setup to avoid problems.