Is there any chance of moving the dish closer? That 350' pretty much puts you out of HD service. Some other considerations = The dish used for HD service actually "sees" three launch locations rather that one for the SD servive so the Line of Sight (LOS) is much wider.
The SWM (Single Wire Multiswitch) dishes require a PI (Power Inserter) rather than power from the receiver....but it is above my pay grade to figure how to amp 350 feet.
You are asking in the right place.........that is a long run!
Joe