Looking for a mechanic in the DC area/advice on buying a car

I'm looking at buying a Regal, and since I know nothing about cars, I was told to have a mechanic who specialized with Regals or Buicks look at the car first. Do any of you know a good one in Northern Virginia?

I'm looking at a 2003/2004 car. Is there something that frequently goes bad with those Regals, such as a problem with head gaskets or something.

Any other input on buying it would be appreciated. I'm nervous to pull the trigger.
Thanks!