to the forum.
You can connect another cable to one of the spare connectors on the quad-LNB. However you cannot connect that cable directly to a Freeview-enabled TV set. You need to connect the cable to a Freesat set-top box first, and connect that to your Freeview-enabled TV. You can get a basic Freesat STB for about £40, or spend anything from that all the way up to a HD-PVR (equivalent to Sky+HD, except with out subscription channels) for about £295.
If you want to avoid buying another set-top box and wish to make use of your spare TV's ability to receive Freeview, then you would need to mount a decent high-gain roof aerial in order to overcome the poor reception in your local area.
I would not recommend buying an integrated Freesat TV for use in your spare room, because at the moment only Panasonic is making them and while they are great quality sets, they are also quite expensive (starting at about £620 for a 32" LCD version). Which is overkill for a second telly, unless money is no object at all ...