I think you should have two keys with Steam for the Ultimate Edition (which I think you probably have with the discount that has been running on there). One for the game and the second for the DLC. I think the Blood Dragon armor is included in that DLC pack thing. I think you can register that DLC key on:
https://social.bioware.com/redeem_code.php
Once registered on there it should be available in both Dragon Age and Mass Effect 2 I think. This all is mostly based on reading around the bioware forum and stuff, so I just hope this helps you out, I'm in no way really sure.