To see WWNY-CBS, real; channel 7, will require at least a Winegard YA-1713 or Antennacraft Y-10713. In fact you may need a matched pair, stacked for additional gain.
http://forum.tvfool.com/showthread.php?t=1024
WNPI-PBS, real channel 23, will require a big antenna such as the Antennas Direct XG-91.
Most amplifiers will be overloaded if you aim either of those antennas at the local stations but I think you'll need a preamp such as the Antennas Direct CPA-19 for the weak signals from the south.
This means you may want to install a smaller antenna for the local signals and then use an A/B switch to select the US antenna system.