I will be staying at Holiday Inn Vista in Shanghai. How far is it to Yiwu international market? What is the fastest and cheapest way to get there? How long will it take?

Also, if I buy some things there from the markets and want to ship them back so I wont have an overloaded luggage, what do you suggest I do? Send thru the postal services? Should I bring my own boxes to have them shipped? Will it be a problem to ship clothes, shoes, purses back? All the post office open everyday and if so what time to they open and close?

Thanks.