Discussion with Luke B about A2 English in Tutor Time made me dust off my bookshelf and produce a list of dystopian novels to have a look at after the George Orwell classics and your two set books:
The Road - Cormac McCarthy ( if you like it try Blood Meridian - now that is REALLY dark)
SlaughterHouse 5 - Kurt Vonnegut (some would dispute it is truly dystopian, but it ticks most of the boxes)
The Trial - Franz Kafka ( a must read for philosophy and politics students too)
Waiting for the Barbarians - JM Coetzee ( savage indictment of apartheid South Africa)
Things we didn't see coming - Steven Amsterdam (Australian fiction, post apocalyptic a la road, but not as bleak).
Dystopian films: Blade Runner; Westworld; Logan's Run ..... better stop now.