Do I need a router?

Hi guys, I just got my shield tablet in yesterday! My internet company is Comcast (50mbs) and my modem/router is located in my basement (Motorola brand, bought at Best Buy, I don’t know the model off hand because I am at work.)

When I went upstairs to stream some GRID games, my internet connection was pretty unstable… a lot of lag. I can usually stream movies and Netflix just fine. Obviously streaming games and videos are different but I thought I would throw that in there.

My question is, do I need to buy a new router to get better wireless connection? Or should I go with something like a router extender. I am a gamer and have my PC hard wired, I never mingled with playing PC wireless until now.

Also if you have an suggestions please let me. I would like to either buy at: Best Buy, Tiger Direct, or New Egg.
Price range: less then $150 preferably but not dead set on it… nothing more then $200 though.

Thanks!

For questions on the GRID Gaming service you’d be best asking questions here

https://forums.geforce.com/default/board/137/grid-gaming-service/