Some tips for improving WiFi performance;
There are other options. Google for WiFi repeaters / range extenders, WiFi mesh systems / pods, powerline ethernet adapters, MoCA adapters.
tv freezes while streaming everytime.
How fast is your current broadband? How fast does it test out on the Comcast test site?
Watching streaming video over the Internet on a computer also depends on the age of your computer and it's CPU. Are you using a newer i5, or i7 CPU or it's equivalent?