Dan, I just saw on BBC news that someone has " somewhat accidentally" found a kill switch in the Ransomware code; doesn't cure the damage, but does stop the spread!
'Although his discovery did not repair the damage done by the ransomware, it did stop it spreading to new computers, and he has been hailed an "accidental hero".'
http://www.bbc.com/news/technology-39907049
* Oh, oh...late edit - the end of this article points out that there will certainly now be copycats of this malware coming out, eliminating the kill switch...