UPDATE:
I’ve replicated this in my test site so this looks like a bug in Slider Revolution. It has to do with how they call Google Fonts. For instance, they call Montserrat like this http://fonts.googleapis.com/css?family=Montserrat:700%2C500
. That does not load completely in IE.
When I logged in to your site again, the font that was used is still Montserrat. I switched to PT Sans and it worked. But, it only worked because PT Sans was added by Cornerstone because you’re using it in a page.

If you wish to use Montserrat in Slider Revolution, you currently need to set it up in the Font Manager and use it for a text in the page so that it will be loaded. Cornerstone calls Google Fonts like this: https://fonts.googleapis.com/css?family=Raleway:300,300i,700,700i,200|Montserrat:300,400,700,700i&subset=latin,latin-ext
. It’s complete unlike Slider Revolution.
I’ll post this in our issue tracker so that this will be reported to ThemePunch.
Thanks for reporting.