Yosemite OSX screwed my Printer!

How is the Epson connected to the Mac? USB, Ethernet or WiFi?

Thank you. A communication error with USB is interesting, in that you have been able to add the printer since you would have needed to do so after performing a reset of the printing system. So this indicates that the Mac can see the printer on the USB port, which is often not the case when you have a communication error.

So what you could have is something interfering with the return communication from the printer. Have you installed software for another device that also uses the USB port? If not, then I would remove the Epson from Printers & Scanners and disconnect the USB cable from the Mac. Then open Finder and navigate to /Library/Printers/Epson and trash the contents of this folder. Next step, empty the Trash and then restart the Mac. Once you have logged back in, reconnect the USB cable and open Printers & Scanners. At this point the Mac should recognise the Epson connection and prompt you to let the Mac obtain a driver from Apple Software Update. Agree to this as the latest driver that was part of the Epson update you downloaded previously should be installed. When this has completed see if this will let you print again.

Were you given the option to download a driver from Apple? If not then there must be other files still resident on the Mac. If wanted to restore the contents of the Epson folder from a backup then you could do that, although that will get you back to you where you were earlier. I would go to Epson's web site and see if you can download the driver for the R320 and install.

Since your Mac won't get the driver for the R230 then you will have to download and install the Epson Printer Driver package. This should resolve the messages about the driver being installed incorrectly and allow you to add the printer.