Are there any modules that can export and import nodes while preserving node id's?
If your backup contains the previously existing users, you could try to recreate your production site locally... Here are the steps I would follow (never tested though):


install a local drupal site with your backup (files should be restored as well) in the production site, via VBO
put your production site in maintenance mode
target all the new / updated nodes since the incident 
export them via Node Export 
reimport them locally (the nids should be preserved thanks to NodeExport and UUID) 
reinstall your local db in production