Unfortunately there isn't much out in C'ville. You're going to have to drive a bit.
Gardens Unlimited in Ladysmith (actually Ruther Glen, but Ladysmith is the exit off of 95 you take to get there) is arguably the best bonsai nursery near D.C. and Richmond, possibly up to Philly and down to Raleigh.
I've posted in the past about the place. Here's a link to the Rappahannock Bonsai club. Bob and Todd are the founders. The photos on the blog are of Gardens Unlimited:
http://www.rappahannockbonsaisociety.com/
They are a tad pricey. But all their trees are excellent. I've been doing bonsai in N. Va. for almost 20 years and have been to most of the bonsai nurseries within 4 hours of here. This one's the best in the Middle Atlantic, IMO.
Randy Clark down in N.C has very nice trees too:
http://www.bonsailearningcenter.com/
The North Carolina Arboretum is holding its annual bonsai festival Oct. 10-11. It's similar to the National Arboretum's show and sale in the spring. Lots of vendors and trees.
http://www.ncarboretum.org/plan-a-visit/event-calendar/carolina-bonsai-expo
To the north, Chase Rosade at Rosade Bonsai just North of Philadeliphia in Bucks County is another standout.
http://www.rosadebonsai.com/
Chase has been doing bonsai for almost 40 years now--possibly longer. He is very very good. The National Arboretum has a few of his trees on display. The nearby river town of New Hope, Pa. is a great place to visit (and keep the spouse entertained) while you look at trees
