Just finished Dragon Age Origin, first time as a Rogue/Archer/Ranger/Bard combo. Took me 76 hours, but i did almost all the side quests.
Will be starting all the DLC tonight, then Awakening expansion after that.
Purchased Dragon Age Ultimate on D2D for $7.50, so its a very good value for the money.
Chronically speaking, Golems and Witchhunt take place after Awakening. Golems doesn't necessarily have to be played after Awakening, as there is nearly no connection with the other games.
But I would highly recommend playing "Witch Hunt" last, as, considering how your relationship with Morrigan was, it really has a final ending for the Dragon Age 1 Saga.