You should be able to get our Silverlight 4 controls distribution as well as various other product files from the "Your Account" page on our website. Just select "Browse all product files" on the "Download List" page.
Here's a link for your convenience:
Download RadControls for Silverlight Version: 2012.2 912 (Sep 12, 2012)
Let me know if that helps.
the Telerik team