The best WiFi extender is GOOD antenna. The best antennas are directional so you might need some kind of of "strength" meter to "dial in" the antenna direction. Many WiFi antennas come with an amplifier, but I don't think and amplifier is that important.
The problem is laptops do not have an external antenna connection. Either you need a USB WiFi adapter.
Google "WiFi range extender" and you will find several recent reviews.