.nzb files can be found from various places and those files contain everything you need to download what you want.
When it comes to ISP providers... I don´t think the retention and completion is on the level you need. You must change news provider. Giganews is what I have been using for years. They now have retention up to 200 days (they will build up that from 100 to 200 days during summer and fall). It will cost you $25 to get those Wookie 1080p ones but I think it´s worth it. Just cancel your subscription after the download.
Just ask if you need any help
