I am interested in this as well.
I believe, to answer TtamCharles' question, follow these instructions:
Once you have edited fruitful-function.php you must then select the desired font from the drop down list as noted here under "Choose font-family": http://themes.fruitfulcode.com/fruitful/how-to/#tabbed-nav12 after following the link "Theme Options" under "Appearance" within the WordPress Dashboard.
I would like to note that I see that there is also a file entitled "fonts-style.css" in the folder fruitful/inc/css, located directly above the "func" folder containing some of the Google font css information, however I am unsure if that is a necessary requirement for adding new Google fonts.
My question is in relation to adding new web fonts, those not from Google, but purchased from a third party, such as MyFonts. I am unable to find the correct file to add the css file location to properly reference the new fonts that I have also added in the same manner as mentioned above by Fruitful Code.
Any assistance would be greatly appreciated.