Sorry, let me clarify, You can buy the AT9 dish and WB68 on your own of course, but D* should/would provide them free if you go through them.
As for your older receivers, you will be able to continue to use those to view legacy mpeg2 streams, however, you will _not_ be able to watch any mpeg4 streams, local or national, you will need the H20 or HR20 (which you can also buy on your own if you wanted) for that.
In addition, your situation with requiring 2 dishes may cause you some trouble with the WB68, as I am pretty sure they don't have the required flexport (or do they?, anyone?), and if you use diplexing, you have yet another hurdle.