Your best defense against this sort of thing is (1) make frequent backups, and (2) keep copies of your most important data on removable media such as thumb drives so they aren't physically available to be hijacked. Hope it works out for you, and if I can help FReempmail me when you can.
Some of the ransomeware doesn’t even stop the attack after you pay. Some of those even demand more money for a cleaner program the source is selling which, if purchased, will add more virii to the system even if it ends that particular attack.