Backup Program Creation

We are a small technology company in Iowa who provides Web based products, including off site backups. Our current solution isn’t working as well as we want and are looking for a custom product. The end product should: -be as simple as possible for the end user – ideally, they should only be asked what to backup; supply a user name and password; -End product should be an .exe -End product must support SFTP -End product should always update files as long as the computer is idle and there is an active internet connection -End product must alert us if the backup fails We are mostly a Windows based shop and our client's are mostly Windows based (Servers/Desktops) so it would need to be native for MS. Thanks!