How to amplify split coax feed from DirecTV box.?

I have 1 box and my main tv is hooked up via rca cables. I have another tv in my bedroom and one in my garage both hooked up thru a 2way splitter that is attached to the coax output on the box. I also have repeaters in the bedroom and garage that forward a remote control signal to the box to change the channel. So all 3 tvs get the same tv show that the box is tuned to, but I can change channels from any where thru my repeaters. Now the question is what type coax amplifier do I need to boost the coax output since the picture is fuzzy due to long runs? Can I use any standard coax / catv amplifier... or for a dish setup do I need a special one? Points guaranteed for best. Im hoping I can just get the cheapest one that you use for standard UHF/VHF/CATV.