Sealed One, might I suggest you explore all avenues before choosing an Order or even a System? I'm not saying there's anything wrong with the Church Of Satan (though I can't say LHP traditions appeal to me at all), but consider looking into other organisations too, such as the Temple Of Set. There's nothing wrong with exploring Thelema and Crowleyanism either, and getting in touch with the OTO for example is fairly easy, if you're into Left Hand lifestyle.

As for the Necronomicon; I was under the impression that the "system" is based on a fictitious book, with fictitious Elementals and Demons? I'm no expert though; please enlighten me.