You can get an all in one modem and wired router/wireless router from Ebuyer for under £50 delivered.
If one of your pc's are next to your main phone connection (where your modem/router will be) then connect that vis a standared ethernet cable.
The remote pc can be connected wirelessly with the wireless usb dongle which they're currently offering free with above modem/router.
Job done for under £50
Log inot
www.ebuyer.com and look up this part number 109521