I'm not altogether clear on the steps you've taken so far. If you downloaded Organisation data by exporting information from either a Landing Page or from a Report, the original data will still be in Workbooks and won't be affected by any changes you've made within Google Docs.
If you've carried out an update to the Organisation data using the import functionality which has resulted in the Organisations being incorrect, you can undo that import (as long as you imported the data recently). Alternatively, you could carry out another update through import using the data that you originally exported. When exporting any data from Workbooks with the intention of modifying it and reimporting it it's always best to include the unique Object Reference in the export so that you have an easy way to identify the right records when importing the updates.
You say you took a backup of the data - do you mean you exported the database or do you mean that you created a new database that was a copy of the original? If you mean the former, you would need to open the zip file and find the CSV file containing the data that you want to restore, which you would do via an update through import. If you mean you created a copy of the database then you can start using that one instead of your original one but this does mean moving all your users from the previous database to the new one and you need to bear in mind any integration that you have on your original database, such as MailChimp, Workbooks Outlook Connector and so on, as well as any API connections that might be pointing at your original database.
Sorry if I've misunderstood your requirements - if so, please let us know and we'll advise further.