Hey, I started a blog with WordPress, and I have some issues with changing the language.

1/ how can I replace this time indication:
Code:
<?php printf(__('%1$s at %2$s'), get_comment_date(),  get_comment_time()) ?>
where %1$s is "30 May 2009" and "%2$s" is "14:05" , into the follwing date: 30.05.2009

The other time setting I could change:
Code:
the_time(M j, Y); ?> replaced by the_time(j.M.Y); ?>
2/ when you hover on the last added (today added) comments, it appears "heute, 15:15" ("heute" is "today" in German). I'd like to have that translated, but have no idea what file to look for.

Can anyone help me out with this, please ?