The 4.5 Standalone software will be available in your Avid account once you activate your 4.5 redemption code (mailed out in a kit).
We've also always made the Standalone versions publicly available so you can go ahead and grab that here if you like:
http://avid.force.com/pkb/articles/e...ftware-Updates
For anyone with questions about ordering the 4.5 upgrade, please see this link:
http://avid.force.com/pkb/articles/f...pgrade-Options
Best,
-Mike Z