Just one problem, the LNB on the dish will be a single view LNB. For Xtra view, you need a twin LNB which is a lot more expensive. Also if you want to use the second channel record on the PVR 2P you need a twin LNB. It may actually have been cheaper just to get a dish and twin LNB because you've had to pay for another decoder and now you will have to pay for a new LNB. Also if you are not going to do the Xtra view set up yourself, someone is going to charge you for it. Try to do it yourself, it's not to difficult. If you get stuck I'll try to help you. Also you can find install guides on the net. If you do the install yourself, when you change the LNB, just make sure the LNB angle is the same as the other LNB on the dish or you are going to pick up a problem.
Check if your single view decoder is an 1131, this is the latest. It's very small. If it is, then Xtra view will work fine with the PVR. From 1110 up, Xtra view is fine.
P.S. Oh' yeah, if you want to use the record on second channel on the PVR, and do xtra view to the SD decoder as well, you will need a signal splitter as well or a different LNB called a quad or a twin LNB 2x4. More cash.