[bargepole]

Might be worth investing in a long cat5 cable so you can connect between your computer and router/modem on a temp basis.

Plenty of the cables available on ebay, put cat5 in search box, just make sure it's long enough. Remember it's only tempory so you can use the shortest route.

I have a similar set-up to you and can now eliminate the wireless network if I'm having any problems because the first thing ntl will ask if they know you have a wireless network is to connect the pc directly to the modem.

Also it will make your initial set-up easier.