Not all source material is HD, but may be upconverted SD. Before you judge your picture quality, look at something like HDNet News that broadcasts in HD to see what HD looks like.
They should have installed the dish(es) appropriate for your area, and typically, you'll either get a good signal, no signal or a signal that breaks up (indicating a weak signal). The picture quality will only be affected by a weak signal and those problems should be obvious. If what you get just doesn't have the sharpness and detail you were expecting, then the source material may be the cause.
There are two HD outputs from your receiver, HDMI and Component. Some have said that one or the other did not work as well as the other input, so you could try changing the connection from your receiver to your TV.