If its the Single Certificate you are after, Chong and I both paid for ours to get done in Toronto. If I recall, it was $300 to go through an Immigration place. I had to go visit a couple of times, but they took care of everything. You will need your divorce certificate (They also asked for my divorce judgment, but I didn't have this, and it did not seem to affect anything), passport, birth certificate (I might have given my drivers license as well).
I took all these documents to the company on a Friday. The following Friday, they had all the documents translated into Chinese, as well as a declaration in both Chinese and English, that said I was not married, that I was divorced from my former wife, that I was intending to marry Zhifang, etc. On that Friday, I went to the office, where they set me up with a Chinese lawyer. He went over all the documents, and then I signed them, to swear they were true.
This company then took the documents to the Ontario Provincial Government to get a verification stamp that the lawyer who also signed, was indeed a lawyer. From there, they took it to the Consulate in downtown Toronto, where they put their stamp of approval on it. Once that step is done, it is a legal Chinese document. I picked it up at this company a week later. So two weeks total.
I can't remember how much it would cost to do it on your own, but Chong had found this place, and if I remember, we would have saved maybe $30 to do it on our own. When it comes to the actual immigration papers, I can be of more help.
This company I am talking about is
http://www.chiaris.ca Both Chong and I used this company. The single certificate is good for 6 months after this.