As to the files, I found some on Amazon for $6.90, though they're actually files specifically for miniatures as opposed to jeweler's files.
This is what I used for files:
Not sure the grit, but they work great!
As for bits... What are you using to pin with? I started with Privateer Press models so I just got their pinning set. Comes with a bunch of metal to pin with and then 2 or 3 bits. Work great for me! It was one of these three, I forget the exact size I bought:
As for getting more bits: I would just search Amazon for pin vice bit set or just pin vice set. That will be what you're looking for. I don't know of any place that would sell individual sets of small bits except for a specialty hardware store or a hobby store(Michaels, ACMoore, etc)