PLEASE PLEASE PLEASE consider rescuing instead of going to a breeder. I recently adopted from here (
Rescue Me Yorkie Rescue), and they are relatively close to you.
One thing to consider - having a puppy is A LOT of work. If you're in grad school, it will be really hard to devote the time that a puppy needs. I got Vinnie when I was in grad school too, but he was already 2 years old and completely house trained. I could NEVER have managed a puppy with the schedule I had at the time. Please just consider that. There are SO MANY wonderful dogs available for adoption. I've rescued several dogs now and have found that rescues are so genuinely appreciative of a good home.