Refinery Quota?

It means that asteroid is being serviced by 0, out of the maximum of 3, refineries. (if you go over, the extra refineries are "wasted")

so how do I get additional refineries, I have never seen the availability to construct more than 1 per asteroid.

Refineries are a separate civilian structure. You can research them in the civilian branch of the Vasari and TEC tech trees or you can research an ability for the Advent trade centers which will have roughly the same effect.

Ok, I found it. The reason I never researched it was the way it reads, will get resources from nearby planetary systems, thinking, I have to use my colony frigate to take over an enemies extractor...

So now that I'm using it, how come it is not getting resouces from my own planets? It seems I have to build a refinery in orbit around each planet, I have trade ports around each planet and with a limited number of civilian orbits available this seems problematic.

Granted, I'm still on 'Quickstrike' trying to beat the AI for the first time.

It basically works like trade ports, it just gives resources and not credits and the amount of resources you get is not based on length of trade route but on numbers of extractors build on the planet or the planets near it.