I am not familiar with Typepad, is this the application you're referring to: http://www.typepad.com
This appears to be a blogging platform on its own, so I don't think there is a way to integrate that into Sitefinity.
However, if you're looking to work with comments, you could certainly do something like Disqus or facebook comments by modifying the blog details template to include the script that loads the comments system.
This is what I have done with my personal site (www.selarom.net
This is easily done with Sitefinity thunder, here's an example of editing widgets from the Sitefinity Getting Started guide: http://www.sitefinity.com/documentation/gettingstarted/editing-widget-templates-with-sitefinity-thunder
If typepad is similarly integrated, you might be able to do the same, but again, I'm unfamiliar with this one specifically.
hope this is helpful!