From a computer standpoint: step 1 physically unplug the ethernet cables of any computers you think are infected. If they are wireless, shut down your wireless card.
Do you have data that you NEED off of the infected computers? If no then format and reinstall the OS. First thing add a firewall (
www.zonealarm.com for example) and patch up. You are going to need a perfectly clean computer to deal with all the password changes, etc.
If you have Data you need to keep then try the scan/disinfection route. I am not an expert but have dealt with some infections before. If you want info on how to disinfect shoot me a pm or I can post here. Most important thing is to get all your passwords for everything changed over and do it from a clean computer.