I would avoid using texts in Standard or Advanced courses, even if they are not part of your study. The marker won't know that, and will assume that you simply don't have your own supporting texts.
If you're going to use Dogville, make sure you talk about Brecht (a theatre practitioner), if don't know about him already. The transparent walls are a very Brechtian technique. Even if you just do a Wikipedia search, that will be a sufficient background for you to support your response.
Another potential suggestion is looking at YouTube parodies of classic films - there are plenty out there, and could lead you on a discussion of subverting the typical 'film' text. Of course, use your judgement, and only use ones which are relevant and stand up to the test of critical analysis.
For students who are after authors who write a little bit differently, here are some on the postmodernism course at the University of Sydney, and some I've added myself:
NOVELS/POETRY:
- Dennis Cooper (Closer, and anything else by him)
- Jonathon Franzen (The Corrections)
- Thomas Pynchon (The Crying of Lot 49)
- E.L. Doctorow (Ragtime)
- J.B Ballard (Crash)
- Lyn Hejinian (My Life)
- Harryette Mullen (Sleeping with the Dictionary)
- Don DeLillo (White Noise)
- James Ellroy (My Dark Places)
- DBC Pierre (Vernon God Little, Ludmilla's Broken English)
FILMS:
- Happiness
- Magnolia
- Mysterious Skin (there is a novel as well)
As a teacher, I would recommend (especially at this stage, with trials and whatnot) to go with the texts you are most familiar with, as they will help you create the strongest argument. Of course you can change texts between now and the HSC, but make sure you are completely knowledgeable in whatever texts you choose.
All the best for your exams!