Welcome to the forum.
Rather than the ANT-751 (a good choice if only the eastern group of signals is of interest), I would opt for an Antennas Direct DB4e facing the main group of signals to the east-north-east. Add a UVSJ and an Antennacraft Y10713 pointed west-north-west to add real CH-11, 12 & 13.
The ideal home wiring scheme is to run all TV outlets back to a common location (AKA, home-run). By feeding splitters in a daisy-chain, you can end up with far less signal at the end of the chain.
I'd suggest running a new line from the basement to the TV currently fed by outside wire. If that's impossible, run a back feed from the basement to the outside to meet the existing cable run. Be sure to seal connections with Coax-Seal, Scotch #2228 or similar material.
I would replace the basement splitter if it has less than 6 output ports. A Channel Master CM-3418 preamp has eight outputs built in. Terminate the unused ports. If the existing splitter in the basement has enough ports to serve all TVs, try the installation with no amplifier. You can add a Channel Master CM-3410 between the antenna and splitter if the need is proven.
http://www.amazon.com/Antennas-Direc.../dp/B0074H3IU6
http://www.amazon.com/Antennas-Direc...f+vhf+combiner
http://www.solidsignal.com/pview.asp...ce=google_base
http://www.amazon.com/Channel-Master.../dp/B002M1EPL0
http://www.amazon.com/Channel-Master...ywords=CM-3410
http://www.amazon.com/s/ref=nb_sb_ss...ctronics%2C270
http://www.amazon.com/s/ref=nb_sb_ss...Ck%3Acoax+seal
http://www.amazon.com/s/ref=nb_sb_ss...tch+2228&ajr=0