The easiest way to change the font to one that isn’t listed in the font dropdown is to view the layer source and directly edit the HTML.
If you’ve previously selected some text and applied a font, when you click the ‘Source’ button, you should see something like this:
To change the font, simply change the font-family rule. For example, to change it to ‘PT Sans’ (a google font), use:
A few notes on this:
1. For Google fonts to work, your theme already needs to have included the relevant CSS to load the google font onto your site. If your theme doesn’t already include the correct CSS, you can install a google fonts plugin – e.g. http://wordpress.org/plugins/wp-google-fonts/
2. The theme editor does not load any google fonts, so you won’t see the font changes in the layer editor itself, but you will see them when you view the slideshow on your site.
3. If you wish to modify the list of font’s displayed in the dropdown, please see this link: https://gist.github.com/dauidus/b2f73c14f1f9dfe3ef63
4. Any websafe font can be used without having to do anything else, a list of these can be found here: http://www.cssfontstack.com/