There’s a certain period of time that elapses between the need of downloading virtual box and of course it’s additions (VBoxGuestAdditions).
AND each time it seems that I loose that bookmark of the beautiful download site of «sun» products.
So… without any farther delays it is HERE.  (  http://dlc-cdn.sun.com/virtualbox/  )

 

At the top you will find all the versions by their number.

vbox2

 

Click the desire version and you will find the addition inside.

vbox3