I need to get wifi in a recently built detached garage. The garage is roughly 200' from my house and modem. I am currently renting a modem/router through Comcast and would like to purchase a modem and router and stop renting. I will be streaming HD content in the garage. I am unsure if I need to purchase a modem and router and extender or modem and two routers, one router in the house and one in the garage. It is just my wife and myself so we do not have many devices.