Go down this forum to the posts on DCA, Flight Safety, and ATP, then read those. I also agree that DCA is a bad place. Flight Safety or a local FBO are my recommendations.

P.S. General Aviation aircraft can be old. Most the planes I have flown were built in the late 70's and early 80's. If you want to become a FO for a regional (aka get 1000hrs), I promise you will fly some of this old equipment.