It's likely the O-ring gasket and rear case seal on the Oil Pump. Plan to replace both the O-ring and reseal the back of the Oil Pump case, as well as the front main seal since you've got it apart anyway and you'll likely ruin the FMS when you re-install the oil pump. Might as well do the valve cover gaskets while you have it apart since most of the stuff will be out of your way.
Check out this article on the repair vs replacement process... http://endwrench.com/images/pdfs/OilPumps.pdf
Here's the timing belt guide for:
SOHC - http://endwrench.com/images/pdfs/2.2SingleOverWin01.pdf
DOHC - http://endwrench.com/images/pdfs/2.5Timing.pdf