Gastroenterology Clinic Interview - help!

I am a student nurse who has been applying for outpatient clinic jobs and was just asked to interview at a local gastroenterology clinic. They perform all kinds of GI procedures and are looking for an RN. I have no idea what to expect in the interview. What kind of homework should I do? I already know there is a GI RN certification so I thought I would mention that I would like to obtain that certification. What else can you guys suggest? Also, what kinds of duties do you think the job will entail?

Thanks for your advice in advance!!!!!!