That should be a great setup!
If you like bass, a second sub would help smooth out your response, but unless you are in a large or open space, it probably wouldn't be worth it.
That receiver should do okay for the time being, but you are missing HDMI and all the delicious sound it brings. A newer receiver would be something I would prioritize over the surrounds. Denon or Yamaha are good choices, Onkyo has been having issues lately.
Denon AVR-1713 | EMP E55Ti | EMP E56Ci | EMP E5Bi | BIC F-12