If you want to do this as static content then you would just need to grab a template with a sidebar (check here: http://templates.marketo.com/) and insert the posts manually in your email using the editor.
But if you are thinking of something that will automatically pull the current top posts from your blog and include them in the email, you would need to look at something like Digesto from Perkuto: http://perkuto.com/product/rss-to-email-for-marketo-digesto
Even then I'm not sure you'll get exactly the functionality you're looking for, as Digesto is designed to send a feed of latest posts not top posts.
It may require some custom work with the API to get where you want to go. If you figure it out would love to hear how though!