How can I update to Aperture 3.6 now that it has been removed from the app store?

I was using Aperture 3.5.1 with yosemite and it was working fine. I updated to Yosemite 10.10.3, the version with Photos in it, and now all of the sudden my Aperture doesn't work anymore. I hear that 3.6 version is fully compatible but Apple has removed Aperture all together from their store so I can't upgrade anymore. I have the CD version of Aperture, so I can't see it in my purchases. Any tips or ideas on how to solve this? I'm feeling fully abandoned by Apple