Any question answered...

Seeing what channels other people are on can help, often most networks in the area are on the same channel and thus interfering with each other. Find a vacant channel, use that channel.

Going a step further, buy a Tomato compatible router, install Tomato and tune the signal for your flat. You can also boost the power using that and also overclock the router for completely unnecessary tech funzies.

Tech question - How does tomato make things better?

Currently in an area with alot of wireless routers, what ever channel there is.