Chinese Tea Set

I have a tea set from China: two cups and saucers, Tea carafe, sugar bowl and creamer. Underneath it looks to be made out of Porcelain, it is painted green with gold accents like a dragon and some other characters.  I'd like to know where it came from, who made it, when it was made and how much is it worth.

My Mother got this from her Great Grandmother. Her great grandmother told her that she got it from a painter ( I think his name was Vos) who painted the Chinese Emperess. He had gotten it from China or the Empress.

Good