Reliable reception starts with the antenna and it's location. An antenna with greater gain would be my first choice when chasing weak signals.
Amplifiers can not / do not 'pull' signal from the antenna, coax or air... They can only 'push' the signal through the loss in cable and splitters connected to the output and if the tuner has a poor noise figure, overcome some of that impairment. How much coax and, what type and how many splitters are you using?
What make and model amplifier do you have on order?
If I were specifically pursuing the KLEW signal on real CH-22 as shown on your TVFR, It would not be overkill to consider large antennas such as the Antennas Direc 91XG, Winegard HD9095, or similar product from other vendors. I might opt to use a Winegard HD7698P aimed at KLEW (131° compass) with the expectation of seeing the signals on real channels 10, 12, 22 & 24.
The challenge would be, "How to make a directional like that, also serve the local signals from the NE". You may find you need to use two antennas. The larger one, on a rotator. There are other options...
http://forum.tvfool.com/showthread.php?t=2882