You can go to http://animecons.com/events/
to see the different conventions all around the world, get a link to their sites, and see when they are.
From what I've already looked up:
Wie.MAI.KAI - October 23rd - At Burgerhaus Kastel
AniMaCo - October 29th - 31st - At Fontane Haus in the Mark Brandenburg district
Wilhelmsruher Damm 142c, Wilhelmsruher Damm 142c,
13439 Berlin (Reinickendorf) 13439 Berlin (Reinickendorf)
J-Con - November 27th - 28th - At Stadthalle Merzig, Merzig, Germany
Those are just the closest ones. Peruse the site for yourself, I'm sure you'll come up with some cons you can go to.
If you do not understand German, like myself, you can use Google Translate for a passable translation of the text. It looks like it's written by a five year old when you do, but at least you can get the basic information. ^^
Good luck, Zeina!