Networking – How to extend the wifi to get 50 more meters of range

First thing is to try different settings on your wireless.

• Try a different channel - you may be getting interference from another source nearby.

• Try different encryption settings.

• Try moving your router to a different location.

Are there any methods, specific plates or materials which can boost the signal?

You're likely to succeed only to degrade the signal or its strength - fine-tuning radio transmission requires special equipment and intimate knowledge (as in schematics and calculations) of the actual gear used.

There is no "magic" tin-foil trick that can be used. If your device has a connector for an external antenna that is your only option - but may well turn out to be of little gain, depending on the antenna you choose.

The actual construction of the walls may be relevant; i.e. if there is a lot of iron bars inside concrete walls, or if there is sun-protection film on sheets of glass... - these would attenuate any radio signals.

Note: there are WiFi devices that operate at 5GHz - as these are quite new, you might get less disturbance (few neighbours have them) on such a device - the reach might not be as long though; higher base frequency also implies less reach.