yikes...this is a scary hack. I will be doing some testing of my router tonight.
Here is a list of routers that are affected by the hack that have been discovered so far. Not all routers that are affected are here I suspect.
Keep in mind that if they already have hacked your router they most likely have all your MAC addresses. Mac addresses are easily spoofed and they would have no problem continuing to use your wifi even if you added MAC filtering.
I would suggest getting a good router that is not affected by the exploit and putting the Cisco into bridge mode. Not sure if the Hitron's are affected by the hack or not so a modem swap may not even help.