Please, avoid this as much as possible, this is plain WiFi vandalism. What if they buy an amplifier with the same idea as you did ? Then some other neighbours join in on the WiFi party and the end result will be useless WiFi for the whole city block.

Consider using a better antenna, maybe a directional one, a foil reflector perhaps, increasing power is almost never the solution (especially as any boost you do on your AP will be useless to the as the quality is determined by the party with the weaker power/antenna which is most likely than not the N810)