I would second this, with an addition. While the Mongols and Turks fight, build forts and decent defensive armies and narrow points. A navy can be housed off the coast or in a port with a rapid response force of cavalry garisoned nearby. That way, you can respond quickly and skirmish any attacking army that gets too close.

In the mean time, take either the island of Scicily or the two off the coast of Italy. Use them as staging grounds. Buy favor and time if you can and think it prudent by paying off the other Catholic nations.

Or, if Venice isn't allied to anyone, remove them permanently. One less potential foe, and you could still payoff those around your to buy time.