I would suggest using PowerShell to automate this if you can install Outlook on the computer. For example, the following Powershell script could start you off:
Add-Type -assembly "Microsoft.Office.Interop.Outlook"
$Outlook = New-Object -ComObject Outlook.Application
foreach ($message in $Outlook.GetNameSpace("MAPI").pickfolder().Items)
foreach ($att in $message.Attachments)
write-host "Attachment: " $att.filename
$att.saveasfile( (Join-Path "C:\download\" $att.FileName ))
# att.Delete() # This will delete the attachment if uncommented
# $message.Delete() # This will delete the email if uncommented
For each message in the chosen folder (Outlook will show a folder picker dialog), it will print the Subject of the message and for each attachment, when the filename contains "backup", will save the file to C:\downloads\
Hopefully, you might be able to adjust this to cope with your requirements. If you need to delete the attachments or the entire email, see the commented-out lines above.