This is an unofficial response and the advice given is mine, not that of bleepingcomputer.com or it's representatives...
Right away you want to pull all the known infected computers off the network, and scan any suspected computers with what ever you got to scan them with.
Think damage control first.
Isolate the infection.
Do you have a domain? (Active Directory)
I may be overstepping my bounds here, but it sounded important.
Please be patient, an official representative will be here to help you soon.
Until then, you should focus on preventing the infection from spreading.
Just my personal opinion.