This doesn't really have the hallmarks of al-qeada. When you compare this to say 9/11, which was intended to destroy, Americas 3 most prominent symbols of power and spread widespread chaos and were it not for a few heroes sacrificing their own lives would have gone without a hitch. It was a perfectly planned and executed attack on the things Americans held most dear. This is 2 yahoos with a can of petrol and a bomb belt.
I doubt this is a build up to something bigger simply because without the element of surprise it is much harder to pull off. Al-qeada doesn't play these games. Hopefully this is just a small group of narrow-minded bigots, who will spend the rest of their lives in the deepest darkest hole we have.