Sorry to hear about the job, but seriously, that's an absolutely asinine interview process, and quite possibly illegal (religious questions are illegal in most situations!).
There's not much you can do about the nervousness besides practice. By practice, I mean you're probably going to have to go through a good number of job interviews before you're comfortable. Also, it's very important that you do shake their hands before and after the process if you can. Don't wait for them to offer their hand. Go up there and put your hand out.
Also, you should have some idea of what they're probably going to ask in an interview. Questions about where you would like to be in 5-10 years are VERY common, so have an answer! Be truthful. If you say that you'd like to still be their personal assistant in 5-10 years, they'll probably smell BS. Being truthful applies everywhere in your interview. If they smell BS at all, you're done.
Good luck next time.