Hey there, and dzien dobry! *waves*
In case you'd like to enter
the masquerade / cosplay competition, you can register through the convention homepage at www.animagic-online.de
(a couple of months prior to the con, I believe) or write the staff an e-mail if you're having trouble with the language^^
This year, the cosplay competition at AnimagiC (at least part of it?) was held by the German Cosplay Championship (DCM) team www.deutsche-cosplaymeisterschaft.de
which means that their rules applied.
Normally, German cosplay competitions require everyone to perform on stage for approx. 1-3 minutes (some competitions have a time limit), walk-ons are less common. Some competitions (like the DCM) involve costume judging as well, i.e. you need to present your costume to the judges up close and answer questions about construction details, etc.
In case you'd like to just watch,
all you'll need is a con pass ^_^ Unfortunately, AnimagiC makes it a point to require everyone
to buy the January/February edition of AnimaniA magazine, which includes one reservation ticket for a con pass. They should have set something up for international visitors who don't have access to AnimaniA magazine, however; maybe drop them an e-mail?
Aside from the cosplay competition, there are other stage shows involving cosplay (so-called "show groups" or musical groups) that you can watch if you have a con pass to get inside the hall.
Unless you're absolutely set on going to AnimagiC, and AnimagiC only - may I recommend Connichi as well? ^_^ Personally, I like this convention better, it's got a really nice atmosphere and location, it's about the same size and a little closer to Poland (in Kassel, while AnimagiC is in Bonn.)
Check out www.animexx.de
(the site also has an English version) for more events and tons of photos of past conventions.