Long explanation short: Panoramic is a poor router. Return it and buy your own modem and router, which I'll assume you did at your previous home.
A modem is just an endpoint on a connection. Its only purpose is to physically connect your house to the Internet. On 1 side of the modem, it connects your house to Cox. On the other side of the modem, it provides 1 port (1 WAN port) to connect 1 device to Cox. You could either connect 1 computer to the WAN port for sole Internet access or you could connect 1 router to share the access. Therefore, there is not wireless feature (2.4 and 5 GHz) within a modem.
It can get confusing if the modem is a combo device: modem and router. It's the router portion, Panoramic, giving you problems. Buy your own equipment.
As long as you buy a dual-band ac router (2.4 and 5 GHz), your N-cards will work.