You can't regain access to your Dragon Age: Origins Grey Warden when you transfer your old save file to Dragon Age II, but your heroic or nefarious exploits will still have a meaningful impact in the forthcoming sequel.
In a recent interview with Now Gamer, lead designer Mike Laidlaw described save importation as more of a world import. The overarching political and geological stuff you've had a hand in, such as what happened with the Dwarves, Laidlaw cites as an example, will be carried over, instead of the specific stats, weapons, and relationship junk we'd expect with something like Mass Effect 2.
"We look at it as importing the world, really," Laidlaw said. "I’ve always seen Dragon Age as a franchise as about more than any one character. It’s about entire an entire span of history and the whole world that’s affected by what happens.
"So, that was our approach and I think the importing stays true to that in the sense that the decisions your Warden made and the person they were all affects Dragon Age II," he continued. "You know, who’s in charge of Ferelden, what happened with the Dwarves, who’s running Orzammar? All of these things are reflected and accounted for in Dragon Age II."
Dragon Age II takes place years and years after the end of Dragon Age: Origins, but the new story remains centered in the original game's Ferelden. And as you may already know, the main character in the game is a voiced character named Hawke instead of your old shoulder-shrugging sociopath. So, with this in mind, Laidlaw's details about save importation sound especially good, if only because it's easy to imagine BioWare simply wiping the slate clean and starting over without regard for the previous adventure.