Feeding a 6 Week Old Puppy

I just got a 6 week old Bugg, that's a Boston/Pug cross, 2 days ago. She's very little, a pound maybe. Everyone is saying she looks younger. I got her 1-12 month dry puppy food, but my husband just told me puppy food is by weight not just age. I'm new at having a small puppy, I never had one this small.

What should I be feeding her? The first night I gave her food she ate it all, then 2 hours later puked it up. After that she's doing great and she's even fatter now. I think she's the runt. She got her first shots and worming with the owner of the mother dog. Please tell me anything I should know about small dogs. I have books on Bostons, but just can't find them.

By Sasha