Goodluck! you must be so excited!
Make sure you find a reputable breeder, One that has been reccommended is a good place to start...the Hobby show breeders are the best in my honest opinion..they shouldn't breed for tinies..but occasionally they may sometimes get a smaller pup that will be too small to breed or show and will be looking for that perfect pet home.
make sure you see both parents..assess the living conditions, are they clean and warm etc, are the puppies happy,playful,bold and heathy looking? check for fleas, an overly swollen tummy may mean worms, check for any discharge from the eyes. Try not to rush into it if you can help yourself..I know its hard!
and remember..there is no guarantee with the eventual adult weight..the breeder will give you a 'guesstimate' but its not set in stone!...
and again..GOODLUCK!