You can do what you say, but I am not technical enough to say how to do it. I once looked into it, and was going to go ahead with it in much the same way as you suggest. I didn't because it was announced that our region is now to get braodband proper.

Search for Satellite Broadband Installation, and look at some of the proffessional companies offering it. Phone them up and talk to them. i am sure they will help.