I have one HD-DVR HR24-500 with 4 regular HD receivers h24-700 ( have entire house connected and working well)and want to swithc a regular receiver to a second HD-DVR HR24-500. Can I just buy a new one and switch it myself or do I need to call direct tvand have an installer do it.? Is there an extra monthly charge I will be paying to do this. Will all the shows I record on either DVR be available on all the tv's. Thanks for any help.