Serial Code/Licence for Photoshop 8 for Mac

I recently bought Photoshop Elements 14 for my new iMac then enrolled on a course. Unfortunately the course uses Photoshop Elements 8 and the differences are quite significant. I have a copy of Photoshop Elements 8 which I purchased some time ago for my old Windows Laptop. I would very much like to use the iMac 26" for course assignments at home, but the Photoshop Elements 8 that I own is for Windows only, so it will not load on the iMac. I have been able to download the Mac version of Photoshop Elements 8 from your website, but obviously the serial code from my Windows copy does not work. I am currently in the middle of a 30-day trial of the Mac version of 8, but what I really need is a legitimate serial number/licence code for that Mac version of 8. Is this possible and, if yes, how much is it and how do I go about getting the code?

Apologies for the length of the post, but I am sure you can see my dilemma!