C.,
Good for you to keep on top of this.
I recommend getting into a SIGNING class for babies - there's quite a few in the Northern Va area- check internet, "Families", "Washington Child"- I can't remember the others (these magazines are free and in front of libraries, some restaurants, Dr offices, various places).
You and he can learn to sign needs so less frustration and more communication between you BEFORE speaking help can come to you two.
Call Childfind in the county you get residence in (any elementary school can tell you the number), and schedule a screening just after his second birthday (sometimes they are booked a month in advance, so call as soon as you know the school district you are in). The testing is not too sophisticated for children under two. Once they turn two, it's more detailed. Amazing what difference one day will does to a score when they are so young...and trust the speech therapist that said to wait and come back, they don't rely on the test scores (only funding does), and his/her observations carry more weight in the decisions.
Child find may also have knowledge of the Mom groups, Playgroups, etc. in the area.