Last time I was in Alexandria, I stopped in the Principle Art Gallery.  They had a lovely collection of mainly paintings, although there were some sculptures as well.  We spent quite a bit of time in there because they had a varied collection.  The staff was very helpful and knowledgeable.   Check out the link to their website below. 

http://www.principlegallery.com/published/

Last weekend I visited the Torpedo Factory Art Center in Alexandria, VA.  There were a myriad of treasures and something to suite everyones taste and budget.  Each artist has their own store within their studio so you could actually watch the artist work and chat with them as they create their next masterpiece.  I highly recommend a visit if you are in the area. 

Visit their website and check out the directory of artists.

http://www.torpedofactory.org/