Hi, Misa,
Since none of the experts is answering I'll try to give you some hints.
I posted a similar qustion, but related to repair bikes.
Thus, the answers do not always fit.
Concerning parts you could check
"Fahrrad Rabe"
Adress: Lindwurmstr. 203, 80337 Munich
Phone: Tel 777719
The shop is relatively close to the center of Munich (app. 3 km)
I hope this helps a little bit.
In general there are many bike-shops in Munich.
Some large shops like Radl-Bauer and Zimmermann are not very good - in my opinion and the opinion of others.
If you need help to repair a bike I can recommend:
Stephan Zwicknagel
Amalienburgstraße 8
81247 München
Tel. 089 / 8119868
The only disadvantage of this shops is that they don't have lots of parts.
But the owners knows a lot and doesn't try to sell things you don't need.
I hope this helps a bit.
Have fun in Munich, Matthias