Modem or Router to replace NVG589

I have a NVG589 with AT&T. I am stuck with AT&T's terrible contract for a while. I plan on going back to Bright House. (My dad canceled my Bright House and went to AT&T so he can get the "free tablet" and the cheaper price even though it was under my name when he moved in with me). I still have another six months to ride out on this contract. Bright House doesn't provide wireless/wifi service with their routers.

I am looking into getting a new modem and or a router to replace my NVG589 for right now so I don't have to deal with my brother (who moved in with me) constantly uploading videos to his YouTube and 100% nuking my network speed. The NVG589 doesn't have a QoS so I cannot give my own laptop or my own devices priority. Thus, when I get home from work I have to kill my brother, unplug his ethernet and deal the night of him complaining.

I most desire a router that I can limit his connection and make my connection the priority. When I get home I want to watch a movie or something, that should take priority over my brother uploading a video to YouTube, or downloading a new giant game. Love the kid, but his internet habits are annoying. Plus it keeps him out of trouble.

I also do some work from home, so his upload / download being ethernet kills my laptop. I don't have a desktop and my laptop doesn't have ethernet support. I use RDCMan to log into my work's network and with my brother's internet habits, I experience extreme lag. This is another reason why I want a QoS service to give me the priority.

I am open to any recommendations. My household is almost exclusively wifi. We do have about 3 ethernet connections though. My brother uses ethernet (I gave him a gaming desktop computer which turned out to be a terrible mistake as evidence by this post). So I need to be able to control ethernet connections and give a boost to my personal laptop and give it priority.

I am terrible at choosing routers. Last few routers I've had outside of my ISP all constantly had issues, but, I believe that is due to everyone having their iPhones connected to it.