Its possible to activate Windows 8 with the upgrade license available now on special offer without having Windows 7 installed on your Mac. You can get tutorials for this on several websites.
Note: You need to own atleast one desktop/laptop which has Windows XP, Vista or 7 installed and licensed.
Getting system builder edition is the easiest way to get your hands on the installation disk but more expensive.
Thanks for the reply.
The thing is we don't have a Windows 7 computer in the house. We have a Windows 8 computer as well as my Macbook Pro-R. So I'm thinking that the disc is my only choice.
My Macbook doesn't even have a optical drive so it's really good to know that there's a download process it seems (If I'm understanding you correctly)