The compass comes around at about 1180 or something like that, but you´ll have to wait for the start of High era to make use of it, for only then the Cogs become available.
Gunpowder enters the field around 1260.

To get back to the pope´s good graces you can also wait until he calls for a crusade. If you´ve got any crusade markers in reserve, start a crusade against the faction the pope wants hit, et viola, you´re back in the Church´s clutches. I´m not sure whether this works with any crusades (I doubt it, I´m not even sure if you can start a crusade - even with existing crusade markers - if you´re excommunicated) , but called-for ones are fine.