In a pinch, go to Whole Foods up the block. They'll have it for sure. The Italian Store over on Spout Run/Lee Hwy, would too I suspsect. As will Balducci's in McLean; that may be a hike for you, though.
I can vouch for it. It makes the best desserts. It's much better than the stuff you'll get at Whole Foods. And the yoghurt (whole milk unsweetened, as you say) is the best I've ever had in this country by a long shot.