Nelo theme using a font not on your list

I want to change the default font to Museo and I am using a font from Typekit (Adobe), this is usually as easy as inserting a bit of code in the head (header.php in this case I believe), and setting a class/font-family in the CSS (base.css in this case I believe). Having done this it hasn't changed the font/s...
I am a novice Wordpress user so don't know my way around it yet so any suggestions would be great