Hello Jeff
Unfortunately, none of the editors currently support importing new fonts, but in the Block, Freestyle, and Custom HTML editors, you can specify the font you want to use in your HTML and the fonts should work as long as the recipient's browser supports it.
We already have a feature request for this functionality. If you would like to vote in support of it or add a comment, you can do so here: http://support.clickdimensions.com/entries/22908180-Add-font-to-ClickDimensions-Email-Template-Editor
