Problem Solved. Thank you Angelo, for the tips. And now I want to share my suffer to help others suffer too in this painfull proccess:
My WP installation is very old, so the data in DB wasn't stored in UTF8 - even changin this setting in WP options or changing the DB charset.
There is a lot of help articles and tips in internet for doing this. But i dont have root access in my SQL, no SED or other pro stuff... i only have the basic access in phpMyAdmin and im no programmer at all. So, here is the "ignorant" solution:
1- use a plugin in WP to change your database to UTF8 (I used this one: http://wordpress.org/extend/plugins/utf-8-db-converter/
2- Export/dump your database as the original format (in my case latin1)
3- Open in notepad++ or wrangler for mac and convert to UTF8 (if your DB is very old and messy like mine, you'll need to spent a lot of hours converting special characters by hand). search and change any "latin1" (in my case) command to utf8. save the sql file.
4- drop all your tables and columns of your wp db.
5- use this command in SQL to change your db charset:
ALTER DATABASE mydatabasename charset=utf8;
6- import your edited sql.
7 - put this line of code in your wp-config.php (or edit if is already there but different):
Dont forget to backup your entire site...A lot of things can go wrong.. I spent 2 entire days in this thing and after a lot of try and error, this was what worked.