Please get immediate help for her. There may be a number of reasons for these symptoms -one possibility is poisoning. Could she have ingested anything that is toxic to dogs?
Or it could be some sort of seizure?
If she's staggering, twitching and drooling she needs to be seen by a vet straight away.
Here is a link to some important resources for pet poisoning, it also lists some of the symptoms.
http://www.yorkietalk.com/forums/sic...l-hotline.html