hi,

does drupal expose its content repository via api's so that external apps can access it..maybe liferay?
is this a good idea? using them together?

Why? That's like saying I want my Ford to be able to drive my Chevy....

If Drupal exposes it content in such a way, you can proably script the import of it into Liferay. Liferay has quite full featured CMS capabilities.

If all else failes you can use IFRAMES or something else to pull it in.

you can use the services module of drupal: http://drupal.org/project/services en then retrieve all content throughout json or something like that