There is no need for the @font-face support. TT Beta supports custom fonts. For typography under the element's settings, you would go to Custom Font. Select the font (i.e. TTF file). Under the General tab you can set all of this under Typography > Complete. When your theme is exported you should notice a directory in your theme called Fonts. Normally that folder is empty. If you choose a custom font then that font (i.e. TTF file) is in that folder.
If you don't have Beta then you can download it. However, when installing it, don't click through quickly. If so it WILL overwrite your regular TT installation. I have mine installed in Template Toaster 4 Beta directory. So when you get to the part where you can select where you want TT installed, just add Beta to the end of it.