G'day fire fighter,
A generic KML map plugin isn't going to get you what you want easily. The problems are that:
1) KML doesn't support circles
2) Google Maps API doesn't let you grab the markers from the KML layer
However, you can look at adding circles to your KML map using a KML circle generator like this one:
What it does is create a many-sided polygon that looks like a circle. You need to punch in the coordinates for your markers, generate the KML, and copy the LineString elements across to your map's KML file. A little tedious, but it'll get you there.
It's possible that one of the other Google Maps plugins will allow you to build your map in JSON or Fusion Tables, giving you access to circles; maybe you can have a look to see what they offer.