One of the Main quests that you might still have is The Art of War from Halina Warhawk to "read the History Book". You find the book at the end of her Tower / dungeon. Look on your map. I think that Halina Warhawk is showing on the map.
(Remember: after you get the history book at the end of this tower, you must go back into the tower and talk to Halina Warhawk. Then she gives you a "Letter of Recommendation" to get you moving along.)
You might want to check the quests on that link to see what you missed. Hope this helped.