Hi again Amy,
This will help you to add a Facebook link to a text widget on your homepage:
http://en.support.wordpress.com/facebook-integration/facebook-badge/
Let me know if you get stuck on any of the steps!
We don't currently have plans to integrate an Instagram button, but we do support images from Instagram!
http://en.support.wordpress.com/images/instagram/
Not quite the same thing, but I thought you might be interested nonetheless.
Cheers!