These are 3 ways to change fonts on wordpress.com blogs.
(1) Changing font families, colors and size in text in posts or pages either post by post or page by page by coding into the HTML editor. http://en.support.wordpress.com/editors/font-size-color/
(2) Changing font colors in text in posts or pages either post by post or page by page using the #4 icon (Select text color – change the text color) in Row 2 the Visual editor. http://en.support.wordpress.com/visual-editor/#row-2
(3) Changing all font families, colors and sizes throughout the whole blog by purchasing an annually renewable Custom Design upgrade and using Typekit Fonts with Staff support. http://en.support.wordpress.com/custom-design/
Note: A few themes do provide for changing font color in the Blog Title and/or optional Tagline and/or links. In the majority of themes font changes to font families, colors and size in the blog title, tagline, menu, post titles, page titles, categories and tags, widget headings, comments, and links cannot be done without CSS editing.
Your theme is a premium theme and read-access to the premium themes forum is now open to all users so you can search to see if your question has been previously asked and answered there. The premium theme forums are at http://premium-themes.forums.wordpress.com/ with separate sections for each theme.
If you are not successful when searching there is a link for the specific Premium Theme support forum for your theme under Appearance -> Themes in your blog’s Dashboard, but do note that the premium theme must be active and you must be signed in as the user who purchased it in order to see it and post to it.