Well, Kyle’s way is much easier than what I did so I would do it his way. This is what I did:
At https://www.google.com/fonts find the font you want and click the plain box with an arrow in it (quick-use box). It is next to the blue box that says add to collection.
On the next page check the 1. style and 2. character sets you want.
Step 3. Copy the code in the “Standard” tab and paste it in the “slider settings” for “Google font settings” where it says “Add New.”
Back on the Google Fonts page step 4. “Integrate the fonts into your CSS:”
Copy the font name so you can add it to the CSS in revslider.
Now go back to “edit slides” in revslider and click on the layer where you want to use that font. Under “Layers and General Parameters” click the blue box “Edit Style” and choose that font family from the dropdown. Now click “advanced editor” and paste the font name where it says “font family” and save.