|You might consider using the LAN over mains adapters - aka homeplugs.|
These are modules plugged into convenient mains outlets. One is connected via a cat-5/ethernet cable to the router; then you can connect any other cat-5 device (computer, printer etc.) to another homeplug wherever, and it's on the network to/with the router etc.
Some of these devices now allow you to extend/radiate a wifi signal too.
Devolo in the UK and Europe) were the first (from Germany), and TP Link, Netgear have similar" and possibly Linksys/Cisco and D-link may have similar too.
Inexpensive, simple to use, and flexible kit...; work out of the box.
Look for homeplug on the web and you'll see what's out there, and what's available in your country.
I am using 2nd generation of Devolo (cat-5 only and 85Mbps) and more than satisfied with them. That version is no-longer available, having been superceeded by faster modules and with both wifi, usb options too.
message edited by trvlr