HI, and welcome!
I am pretty sure the sneek peek can't be bought seperately, or can it?
But if you already payed moey for the game it depends where. On BB site or on steam?
If you bought the game on steam it should be in your games library automatically.
If you bought it via BB site you should have received a key via email.
Check the email account you use for paypal and check the spamfolder too
Hop this helps! See you online soon!?