Looking for a mechanic/dealership in Balto/Wash area

[CindyLouWho]

I hate to sound like the stereotypical girl, but... I recently bought a 2006 Boxster S and this thing on my dashboard is telling me it's time for routine service. My car is still under the factory warranty. Does anyone know of a decent mechanic and/or dealership in the Baltimore/Washington area where I can take my car for service? Also, I have a problem shifting once the transmission is warmed up. I have the tiptronic transmission. Any ideas what the problem could be? Please tell me it's not going to cost a fortune to fix it!