Certifying Documents

Hi!

I am currently a Canadian living in London but running up against a lot of obstacles with having just a 2 year visa. To make a very long story short, I was told to try to contact the German consulate in London to see if I was able to obtain a German passport. I was given a document to fill out by the consulate but I've run up against a problem: I need to have all documents (marriage licence, birth certificate, etc.) to be certified by a German authority.

Everything is in Canada currently (with the exception of myself!) so I'm wondering - does anyone know where to get things certified by a German authority??