Check this for an understanding of diffraction:
http://www.hdtvprimer.com/ANTENNAS/siting.html
As for another antenna, maybe. I would not have chosen the one you have for your location. However, since you have it it costs nothing to re-aim it. Start at 142 degrees (using a compass) and see what happens. If you loose CBS and ABC start moving it back towards 221 and hope you can find a sweet spot that gets everything you want. If not, let us know.