In order to add more fonts to your tinyMCE editor you would have to edit this file:
ac_global/js/editor.js
There are some functions that look like this:
ac_editor_init_normal_object, ac_editor_init_word_object, ac_editor_init_mid_object
You would have to add another section to one (or all) of those functions
called "theme_advanced_fonts"and then list the fonts you wanted to use.
Like in this example:
http://tinymce.moxiecode.com/wiki.php/Configuration:theme_advanced_fonts
I would suggest using the second example, because it's easier to understand.
Add it to the ac_editor_init_word_object section.
You can of course add and remove as many fonts from that example as you want.