try the cm7777 preamp and see what happens. only thing to look out for is overload. the first sign is the signal level will go down some and going up as you point away from the towers. if you look at old style analog pictures, look out for co-channel interference etc.
in regards to the monster 4 way splitter. The $5 splitter at lowes/home depot, ideal brand for example works just as good, please return the splitter and save yourself some money.
in splitters, bandwith of 5-1000 to 1500 mhz is plenty . 2250 mhzs for satellite. applications. with 3 way spliteers there are a few different versions.
5.5,5.5,5.5
3.5,7.5,7.5
3.5,6.5,6.5