thanks a lot. Is there a list or link where i can see how to define other formats like 00,00?

here you should find everything about formatting, but it can take a while to get through the documentation.
http://docs.oracle.com/javase/6/docs/api/java/util/Formatter.html
http://www.xinotes.org/notes/note/1195/

its quite similar to printf() in "C", so, you probably find better documentations by searching for that.

Also see the Processing reference for useful functions:

nf()
nfc()
nfp()
nfs()