The extra five cards are from promo codes released around the time that PAX Australia and ComicCon we're going on. Here they are (in no particular order):
Code 1: GKSNDR
Code 2: DWNNDR
Code 3: FTHPTH
Code 4: TRCKSC
Code 5: PRSTTT
Code 6: RSNGSN
Code 7: XBXBDZ
You should be able to input these in via Extras -> Promotional Unlocks
Funny thing I just noticed that all my decks are reading xx/
36 instead of xx/35, and as far as I can tell there's no way to unlock those extra cards yet. It irks me a little.

EDIT: Just realized I don't have the last cards unlocked because I only used five codes instead of six. Carry on. :P