Greiner and Hartmann Family

Could anyone tell me where I could find the birth, death and marriage
records for the Dusseldorf, Munster and Hamburg areas of Germany from
1870 to 1910. In other words, does anyone keep an index of these
events and who do I contact to get a look at this index?
I am particularly interested in finding the marriage certificate of my
great grandparents, Robert Herman Wilhelm Greiner and Wilhelmine
Dorothea Hartmann, as well as their respective birth certificates.
I have already looked in the I.G.I., but as most people have proberbly
noticed, the Westfalen area has not been indexed at this point in
Thanks for any help,
Leonie Greiner.
P.S. I live in Australia, which can make things a little tricky to
track down.