[SixOfSpades]

Hm. Well, as there is no actualy map area named The Stronghold, I'm going to assume that you aren't especially familiar with the game. I'm not talking down to you or anything, I'm just saying that you probably didn't try to leave the city in the precise, correct way.

Go to the City Gates map. In the upper right-hand corner of the map, there is a large archway with some illegible writing scrawled above it. You have to direct your party to go beneath that archway. Move your mouse around on the far said of the arch--when the pointer turns into what looks like a wagon wheel, click. Boom! You can now travel to all of the out-of-town areas that you have opened up. If you open up new ones (like the Umar Hills) later on, you may have to do the City Gates thing again to make the new area accessible.

And yes, I want to shoot BioWare in the knee for making everybody have to do this stupid City-Gates thing in the first place.