Business trip to the Mother Company in ShenZhen

Dear sir:

I am the employee of a company which has factory in ShenZhen, China. I have a US passport and locate in San Jose, CA, USA. Can the US company send me an invitation letter for applying Chinese VISA for visiting the factory? Or the China factory has to send me an invitation.

Originally I was from Taiwan. That passport had been expired. Do I have to bring that passport with me?

Can you let me know how much I should put on the Cashier Check for all the process plus postage?

Is there any other documents that I should bring in addition to the following:, 1) 2 photos 2) Invitation letter 3) US Passport 4) application form 5) Taiwan passport(?) 6) Cashier Check 7) document for name change.

Thanks for your assistance.