This is an amazingly common question, Bioware should really make it more obvious since a lot of people don't seem to understand it.
The fact you've got all this stuff unlocked, along with any DLC you've bought and any codes you've input off the little cards you sometimes get in the case with the game, are all stored in your EA account. You can see the various items linked to your account by going to Profile -> Your Registered Game Promotions on the sidebar of this forum.
When you play DA2 while signed into your EA account, those items will automatically be unlocked. For example, with the Blood Dragon Armour promotion in DA:O, it was simply in your inventory at the start of the game or when you loaded up a save after unlocking it.