I'm currently on a visitors VISA, in China, and I need to apply for a work permit.

I'm living in Mianyang, in the Sichuan province, and I understand the process can be different from province to province. It seems there is a lot to organise. Where can I find an agent to act on my behalf to organise this? Or is there a Visa office I can go to to discuss this? Thanks for your help.