One could recover from older infections by file-restoration programs and even decrypting the crypted ones (using the leftover deleted key).
None of these options work anymore (unless you pulled the powerplug/battary when your hd started to perform excessive work (nobody did or recognizes that, especially on non-tweaked FF/Win8 hd-killing software)).
After full encryption the key is shredded (no longer just deleted), as are the restore points and encrypted/deleted data.
The main point I'm posting this answer however is to warn: the machines that I've had to work on ALSO had infections in the system-recovery (I mean, 'back to factory' aka 'reinstall windows'), however on most machines this led system-recovery to fail entirely, thank [enter deity here], otherwise one could get the illusion one at least got their OS back.. (not realizing the hostage-software and identity-theft malware that is also shipped (hey these guy's and their 'support-employees' got to get payed even if the victem doesn't do it themselves..) would be ready for another go at it..)
If you got this pest, bring your pc to an advanced repair person/center to recover your OS license, wipe correctly and reinstall legally (you had a legal machine right?).
Also clean all your USB (I had one customer f up his machine the moment he got home with an infected USB stick) and external drives!
PS: don't waist to much time investigating your options, after a week the ransom will be double (and so on).
That being said (warned!!!), victims of older cryptolocker can visit: http://www.decryptcryptolocker.com/ to get their data back for FREE.
"All they have to do is submit a file that's been encrypted from that
we can figure out which encryption key was used," said Greg Day, chief
technology officer at FireEye.
Source: http://www.bbc.com/news/technology-28661463 (here you can also see a picture and the name of the one who did this to you.. (and stole over 3Milion $ from justice departments, law-enforcement, governments, corporations, and you and me).
It might pay off to backup the encrypted data securely and wait..