Someone, (The Sky Installer?) would have connected the cabling in the ceiling of your old place to create that "Feedback" system, so that the Sky signal would then feed back to the bedroom.
Most houses are not wired up that way as standard; Sometimes a new cable even has to be physically pulled down inside the wall to create that "feedback" setup.
So what I'm saying is that you will need to get someone to first configure your system for the "feedback", then you (or they) can connect up the modulator to the Sky receiver, and then to that feed back cable.
It's not just a matter of moving into a new house and connecting things correctly behind the TV in the lounge. Sorry.
We're based in Hamilton and cover the Waikato but, unfortunately, you're just a bit too far North for us. So hopefully someone who services your area will read these posts.
What's wrong with the picture? Is it grainy?, has it got wavy lines across it? is it in B & W? and I assume you are talking about the picture from the Sky receiver?
I assume the tv in the lounge is connected via hdmi cable ?
How have you connected the bedroom tv to the modulator ?
To get the best picture possible via RF connection you need to connect the modulator and bedroom tv directly using RG6 coax.