How I can get new passport or renew passport in China for Pakistan person

Dear sir,

I live in Kashgar near urumqi and i have business visa. I have one shop and flat due to investment in a project. My passport going to expire and for new passport or renew passport where should i go. Can i get new passport computerized again from China or they will give me extension in validity time in my current passport.

Mr.Tariq
Kashgar