Getting the most out of your Wi-Fi can be tricky and depends very much on where you live. For example, some areas are more densely populated, so getting good performance can be harder, also, some buildings are better are letting signal through the walls than others.
HomePlug or Powerline are both very good alternatives to Wi-Fi. This is the technology that puts your network, or data, over your mains power cables in your house. This is very good when Wi-Fi signal is poor.
What advice would I give, well, here is some: