Catalytic Converter or Head Gasket

So my car stalled on me some months ago on the
interstate and I called a tow truck to bring it home.
It still starts and runs however will not go over
35mph. Known issues on this car already are
power steering pump leaking at the top near the
tank and hoses, cracked motor mount, oil pan leak.  
My fiance sprayed sealant on the oil pan for a
temporary fix. I had the muffler and alternator
replaced already. I know the oil in the car is slightly
dirty but there is no water in it. All fluids have been
checked. Transmission fluid is fine. I'm uploading a
picture to show what we found on the ground a
week prior to it stalling out. Also a mechanic just
informed me that my water hose is dry rotted
which is clearly visible you can see where it is split
on both sides.