Absolutely brush up on your AS/A-level texts - if you can remember a couple of quotes, that's impressive (I ended up reciting several lines from 'Macbeth'!). Be prepared for a question that will make you have to think - for example, you may be asked about a theme or plot device in one of the texts that you haven't considered at A-level.
Check over your Personal Statement to remind yourself of what you said; you'll probably also be asked to talk about books that you've read outside the A-level set texts. If you don't understand a word the interviewer uses in a question (for example, 'universality'), don't try to cover that up - just ask what it means and then continue with your answer. The interviewers are not out to trip you up or make things difficult for you; they just want to offer you a challenge and hopefully have a nice chat about books!
The written exam is basically a piece of analytic writing - so the basic stuff like form, structure, vocabulary/any repetition thereof, why the author might be doing that, if it's poetry then metre, any enjambement, rhyme scheme, etc. Just do your best to pick the passage apart and write about bits you find interesting, essentially. If you're lucky enough to recognise the passage, don't say what it is but skirt around it - for example, if presented with Sonnet 18, one might talk about how it is reminiscent of Shakespeare, obviously a sonnet because of the structure, etc. I highly doubt that you will be given something that recognisable, though!
Best advice I can give, though: breathe, relax, smile and be yourself. Good luck.