FFXII - Walkthrough - Jahara
Save your game, and buy some maps to complete the Ozmone Plain and the village of Jahara.
Talk to the guy blocking the bridge; you're let into the 2nd area of Jahara. Next, talk to High-Chief Zayalu; he tells you you need to speak to the Great- chief.
Go on to the 3rd area, and speak to the Great-Chief. Numerous cutscenes; Larsa is back in your party as a guest! Save your game, and outfit yourself with weapons/armor from the shop if you need to upgrade.
If you bought the Ozmone Plain map like I advised you to, you'll know where to go - far east (the arrow pointing southeast is for somewhere else... coming up later in the game)