Extend GL.iNET WiFi range

Hello,

I have AR150 with 1 ext antenna, that came with the device.
The AR 150 is wired to my home router.
Unfortunately the AR150 signal is pretty bad.

I would like to extend the signal to outdoor in order to offer signal to people out there in a radius up to 500 meters.
Any suggestions? What GL model should i use, what equipment should I connect to it and how?
Any high power antenna would work? What about bullet with omni antenna, or mikrotik…?
Apart that, If i will replace the small antenna it came with with another amni antenna, would it make it a little better? Which antenna would you recommend?

I am kind of lost here so I would be happy to hear any suggestions
Thanks