Internet speed

I pay for my internet almost $50. Yet, cannot watch any video without buffering, loading, or failure to connect to internet. Laptop, blu-ray etc. The signal is terrible in my house, while my modem and router are upstairs, and blu-ray is downstairs connected through wi-fi, Netflix, VUDU nothing would play right. It's so frustrating, I'd agree for a faster internet as long as I know it would work good. Please help out