If you want to use them for DA2, then I'm sorry but you're out of luck. The Social info is only the character's basic stats and a small thumbnail image, the same as is uploaded to the Keep. You'd need an actual DAO save file to import into DA2 which would have been stored on your computer. Reinstalling the game won't restore them if you don't have them anymore, but you can recreate your Warden's save for import to DA2 with this save generator. It is rather buggy, so I recommend a tutorial from here (Editing World Vault, nearly at the very bottom of the files page) to check for and fix any errors.
If you want to carry them both on to Inquisition instead, all you need is the Keep and you're all set for that. No need to reinstall or even replay the games. 