Anonymous wrote:DC, but close in Montgomery County would be fine too.
I would try Sarah Wayland:
http://www.parentchildjourney.com/about/
She's actually in Riverdale Park which is PG, but easily accessible from DC or MoCo.
If she doesn't have any availability, I would try calling Auburn or Ivymount Schools for recommendations. Even if your kid doesn't go there, they recommend people for parents of students all the time.