I would recommend a pfSense, https://www.pfsense.org/ old PC with a couple NIC's in it, this can make sure your traffic is passed first and all others basically wait, this will improve ping times, the old PC can be a simple Atom processor with 1gig ram, dumpster diving is a great place to get such a machine.if you want another option Ubiquiti Edgerouter is a prosumner class router which uses a variant of Vyatta, I am a great fan of PfSense, easy to setup and lots of expansion options. The WiFi part of your network I would hand off to a simple access point and not use a Router-Wifi Combo