Passport renew from your office.

Dear Sir/Madam:

I'm Lenalie G. Braza. I'm working in one of the universities in Henan Province.
My son's passport will expire on July 12, 2014. We are planning to go back home on June 2014. I want to ask the following questions:
1. How many months or days do we need to renew before the expiry date?
2. How many days are the processing?
3. What are the requirements for renewal?
4. How much does it cost?

I'm waiting for your reply. Thank you very much!

Yours,
Lenalie