A:Answer A couple things:
1. If you don't have a home phone line, I would suggest getting rid of your Comcast two in one and opting into your own modem and separate wifi router. A gateway does very little justice in a home your size.
2. In order to make the velop system an access point, which is what you want to do to make it sort of a wifi extension, you'll have to first call Comcast and have them turn your gateway into a bridge. This will bridge the connection from your modem to your velop router and allow that to be used as a router. You'll have multiple nodes so using them as a blanket wifi system is as easy as that.