you can extend your tourist VISA to a "Visa for an intended marriage in Germany" if you getting married to a German. I was told that your VISA will be extend for another 90 days.
here is an English explanation :
http://www.new-delhi.diplo.de/Vertretung/n...__marriage.htmlIf you marrying a German - remember that your paperwork has to be translated into German by an official translator and have a Court/Official Stamp AND
It is best to do this all in Germany as it often happens that applications are rejected because the translation was not done in Germany and they are really fussy.
Good luck!