Hmm, I didn't do that module but I would say that if they're literature, it's much better to read them in the original German (takes longer but can always wikipedia the synopsis), though a lot of people do just read translations - however don't tell the lecturers if you do that, they hate it

For reference/non-fiction books, get them in English, reading that in German is such hard work. Reminds me I've got a couple of those for final year, so not looking forward to that!