Completed and tested Circuit to increase range RC Helicopter

We are looking electronic engineers/designers/hobbyist to provide us a tested and completed circuit to boost the range of the Remote Control Unit of RC Helicopter. RC Helicopters we are talking about are the big ones available in the market. But we really like to increase the range up to 6 to 10km. Like the walkie talkies available in the market got very high range. If you want to suggest any specific RC helicopter, we can try to purchase it on line. We need to use it for a observation UAV or MAV. We are open to suggestion. The project we have got belongs to forestry department. We also looking for the long range video broadcast with stabilization. If you suggest any ready made hardware that can fulfil our requirements, we may go for it. Or, if you like to resign it your self, that might do as well. But the circuit must very reliable and stable. Booster could be easy idea, that we could plug with the commonly available RC controls and increase the range. But then again, this is just our idea.