How to add a widget area between blog posts in Genesis Framework?

This thread – http://wordpress.org/support/topic/how-to-put-adsense-after-first-topic – explains how to add something after the first post so I would assume you could change the 1 to a 3 to have it display after the third?

And this page explains how to add a widgetized area: http://quirm.net/2011/09/15/widgetizing-any-page/

So you would put the php for the dynamic sidebar where the first post tells you to add the adsense code.