Yorky or Silky?

Question
We've just recently adopted a small terrier.  We were told she's a silky but then a saw a picture of a yorkshire so now I don't know what she is. How do you tell them apart.  Also, she just went into heat.  I've always had male animals.  How long does it last and how many times per year will she go into heat?  Apparently the people who owned her before weren't very nice to her... she's a little skittish, especially around my son.  Turns out the previous owners had 3 boys!  She's only been with us 5 days and we're trying to get her papertrained.  We think her previous owners left her outside.  Any suggestions would be appreciated.

Thanks so much!
Sheri from Texas

Answer
1. get the dog fixed. having her go through heat cycles increases her chance of mammary cancer, pyometra (infected uterus) and costly vet bills  if you decide to breed her and have to have a c-section done on her.

2.  take her to the vet for an exam.

3. give her time ;)  she came from one stressed enviorment to another. in time she will adjust.