Hello and welcome!
As Dave said, what you need is an antenna with VHF reception capabilities. You have two local channels broadcasting in VHF. WJLA (ABC, ch 7) and WUSA (CBS, ch 9). The other low numbered channels you see (4.1 and 5.1) are actually broadcasting on UHF frequencies (48 and 36, respectively) and only "show up" as low numbered channels through the magic of virtual channel mapping (
http://en.wikipedia.org/wiki/Virtual_channel). With digital TV, the channel number you see on the screen is not necessarily the same as the channel it is being broadcast on.
The Radio Shack DA-5200 is designed for UHF-only. You might get lucky an get a little bit of VHF signal through this antenna, but it's not what it was designed for.
A good high-VHF and UHF combo antenna for your situation would be something like the Antennacraft HBU-44 or Winegard HD7695P. These kinds of antennas are too big for a living room installation, so you're looking at either an attic or rooftop installation.
Signal quality is better if the antenna is installed on the roof (less building material to go through and fewer objects to get in the way), but some people prefer an attic installation because of the better protection from the elements. It may be necessary to go up one antenna size (like HBU-55 or HD7696P) for attic installations to compensate for the building loss, but that really depends on the building construction, and can vary from one situation to another.