Renew South African passport

I am running out of pages in my South African passport and need to get a new one. I am currently living in Dujiangyan, Sichuan province, so I would need to travel and take time off work to do this.

How long does the process take? What are the fees for getting a new passport?
I can't find much information online. I was wondering if there are companies that will help you through the process, airport pick up transport to the embassy etc?