|The Powerline Ethernet Bridge is a somewhat unusal device/approach (and a new one on me). It enables you to use the mains instead of a cable connection between a Router and Computers etc. This is different to Wifi - if that means anything to you.|
This would be worth reading:-
Look at the first diagram given. The dotted line is the "ring main link" between the upper and lower portions of the diagram. It uses your domestic mains as the transmit/receive medium between devices.
At first glance it seems you require an ADSL Ethernet Router and a Powerline Ethernet Bridge twin pack. However it would help if you can explain how many computers you have, (PC's and Laptops) and what you are trying to achieve. Also, what exactly are your present internet arrangements? It looks like a simple "plug-in" activity once we know a little more.
From Google it seems to mention 230V so I assume this is a UK device - I'm in the UK too (and also 74 next birthday LOL).
You can forget about the wireless mouse. This just works directly between your mouse and your computer and has nothing to do with the bridge or internet connection.
some other bloke...