|If you want to do it wirelessly then you can get 'range extenders' which will do the job. I use a netgear one which works fine, though I've seen people have had issues with setting it up (it's the WN3000RP). You can also use mains 'homeplug networking' which works well, especially if you use it on a fixed PC - cable plugs directly into the adapter. There are many different brands, all do much the same thing.|
Finally, you can use cable and switches which is a bit more involved but is the 'solid' way of doing things.
"I've always been mad, I know I've been mad, like the most of us..." Pink Floyd