The key to better WiFi isn’t a super high powered $400 router from Best Buy. That’s like trying to light up your bedroom by putting more lights in your closet.
The key is getting as close to the WiFi router as you can, or centrally locating your WiFi router. If your home is a bit larger, getting a kit that can spread out the connection is the best solution.
A few options
MESH networking.
This uses remote repeaters with powerful antennas to boost the signal around your house. current recommendation:
Homeplug aka Power Line Ethernet WiFi extenders
these make use of your electrical wires to connect multiple WiFi adapters around your home.
http://www.bestbuy.com/site/netgear-powerline-1000-network-extender-white/4760603.p?skuId=4760603
Wires
yep, good old-fashioned wires. Your WiFi is a shared connection, so having a bunch of devices hooked up can slow your WiFi down substantially. If you connect wires to some of these devices, you can free up WiFi service.
You can mix and match the technologies above also. Using Homeplug adapters to hook up desktop computers and WiFi extenders improves WiFi availability and range.