It's been several years since I have used Toast, but it would seem your problem with your printer driver holding you back might be solved with a Mac OS upgrade to a later version. That's because printer drivers are provided by the Mac OS itself... unless you are in an unusual situation. Later Mac OS versions will (probably) carry later drivers. What is your printer make and model?
You might want to go to https://support.apple.com/en-us/HT201465 and see if the latest software for your printer is available. If it is, I would recommend an OS upgrade. Although Apple does not support it, you could try (if you are so inclined) to upgrade your 2008 iMac to Sierra (Mac OS 10.12.x), which might carry a later printer driver for your printer (whatever it is). To do that, you would need to go here: https://www.trustedreviews.com/news/install-macos-sierra-older-macs-2937027 and follow the instructions.