If you would like to work with a local company then you can Google web design companies in the DC area. Take a look through their portfolios, read some of their blog posts, get a feel for who they are and what they've done. Find 2 or 3 that you like and get a preliminary meeting with them to find out if you'd like to work with them. If you think they'd be a good fit, ask for a proposal and references that you can call.
I agree with NogDog - unless there is a really good reason, don't make WordPress a requirement. You could find a great company that you really like that uses a different CMS or has their own CMS (our company has built our own).
Don't be afraid to share your budget range, it will help the company provide a proposal or plan that is suited to your budget, instead of guessing.
I would definitely recommend a company over a single person/freelancer. If your single person gets a full-time job, goes on a trip, etc, you're left hanging. With a company you have a more diverse skill set to draw from, and if one person leaves there are others to pick up the slack. In the long term a company will serve you much better than a single person in most cases. We have picked up the pieces from half-done freelancer projects many times.
If you're ok with working with a company outside of your area, you can check out our portfolio: www.boxclever.ca
Good luck with the project!