First the Bad News
You can change behavior but you can't change temperament. It sounds like you have a combination of the two. Most breed standards, either expressly or by implication, direct the removal of the shy temperament from the program. It's so important that it is one of the few aesthetic traits that warrant removal on it's own, normally it takes three to cause removal. But in these days the standard seems unimportant so we get many more puppies with shy temperament. Since your breeder admits she doesn't have the time to spend socializing the puppies the good news is even better.
The Good News
The Neural Pathways in your puppy's brain are still under construction and you can affect how they progress from this point. Contrary to some advice it will be helpful to take the puppy to loud places with new things and not offer comfort. This might sound mean but which is worse, protect her now and sentence her to a life of fear? or expose her now and set her free? Her startle/recovery reflex and her ability to soothe herself on her own is very important. Holding her a lot is fine as long as you don't pick her up to soothe her when she is afraid. Let anyone pet her that wants to and if possible slip them a treat in advance so that she associates good things coming from unexpected places. When at home use an "umbilical cord" to attach her to you at all times unless she is in her crate. This will end the "she won't come to me" problem immediately and is a helpful potty training aid as well. Most of all never....ever...treat her unless she does what you want. Encourage her but do not make excuses for her, she deserves a life free from fear and you can give it to her. Good Luck!!
