I specialize in Capitol Hill, but I work a lot in the rest of DC (and only in DC). Are you south of the Georgia Petworth Ave Metro? West of Sherman Ave? If so, you are most likely just fine. Petworth is a location that has taken a big hit - it is the location in NW that arguably had the highest foreclosure rate. However, most of that inventory were homes that hadn't been updated. And they are clustered closer to Brightwood (i.e. north of Emerson St NW). I can site 4 comps that sold in Petworth near the metro at 599K with the same stats you provided above (on - 2 on 11th, and 2 on NewHampshire). Additionally, the effects of Columbia Hts is really moving north putting pressure on Petworth, even as developement around Petworth is also growing. My assessment is that Petworth will be one of the "bohemian" centers of the city as it is attracting artists, and independantly owned businesses.
Best of Luck,