There are several online backup services that will backup your data on an automated schedule to an offsite location and at the same time keep a copy of your backed up data stored on a local external hard drive. Another option is to purchase 2-3 external backup drives and keep 1 of them at the office at a time for daily and weekly backups. You can rotate the drives on a weekly basis to an offsite location so that you are only using 1 at the office at a time. This would allow you to keep a fairly recent offsite backup in case of natural disaster. Rotating multiple external backup drives is an older method but still effective if managed properly.