You have quite a few signal available to you. They're spread wide though, so you'll need an antenna with both gain and very wide forward beam.
Antennas Direct has the DB8e available for pre-order. It's based on the DB4e which was engineered to do well with real channels 14 through 51 (52 through 69 were taken for cell phone, PCS and broadband in 2009) so it has more gain than the old 14 to 69 designs.
The DB8e is adjustable. You can set it up as a traditional 8-bay panel antenna to get maximum gain in the forward direction and, you can turn the left and right panels relative to each other to trade some gain for wider beam width. I would suggest you set the antenna elements for 30° to 45° off broadside. This will direct gain so that you can receive from the south and the east simultaneously.
If you want to add the signal from WTVI on real channel 11, add an Antennacraft Y10713 or Winegard YA1713 pointed toward 157° compass. Use a UVSJ to combine to UHF and VHF signals.
Presuming the existing distribution panel has only a passive splitter, I would suggest the Antennas Direct PA-18 preamp, installed close to the output of the UVSJ which would be mounted on the mast just under the antennas.
http://www.antennasdirect.com/store/...r-Antenna.html
http://www.antennasdirect.com/cmss_f...s/DB8E-TDS.pdf
http://www.antennasdirect.com/store/..._combiner.html
http://www.antennasdirect.com/store/...e_amp_kit.html
(I would shop for price at Amazon, Best Buy, Solid Signal, 3 Star Inc... etc.)