Problem: The Router/hub you have connected to the Internet cable (ADSL/VDSL/ Cablemodem/ Optic Fiber FttH cable) has Wi-Fi but it reaches only a couple of rooms. The walls decreases the broadband you thought you would get.
You can buy Wi-Fi boosters or Wi-Fi extenders on the powercables, but that will blast your neighbours Wi-Fi out of the ether, and to is very unsafe because its radiation can be monitored outside too.
A much better solution is to employ Plastic Optic Fiber dual cable and slide it through the 230 AC yellow lastic pipes in your home and fix a Wi-Fi picocell on the end of that, with wireless enough power in/out to cover the room.
These cables and do it yourself installation boxes are for sale at http://ls2connect.nl/ in Harderwijk, The Netherlands. For the EUROPEAN MARKET.
jaap van till, TheConnectivist