I've bought a lot of the materials out there (thirsty for knowledge I guess), my recommendations as follows:
1. Aviation Theory Centre - great books, good diagrams, lots of practice tests. You can get the full kit at a discount.
2. Val Dyson Holland - his prose sometimes seems a pedestrian and it is annoying that they are in a binder and not proper books but covers all of the syllabus in great detail.
3. Online Aviation Theory - Ron has built some great practice exams but the UX is pretty buggy and the actual theory side of things a bit patchy
4. Bob Tait - I have the eBook which seems to be one of the few available on iPad plus I have the practice exam sets. The criticism I and a few others including my experienced instructor make of Bob Tait is that there seems to be the bare minimum to cover the syllabus and nothing more...your experience may vary!
As for the difference between the licence types, I'd suggest for the CASA RPL or PPL you refer to the CASA website as the syllabus and sample exams are there...for free.
If your instructor won't tell you the difference between licence types I would be seeking a new instructor. What a knob.