Gun_Metal_Grey,
Going by your second picture, the arrow pointing to 'unknown gasket' and the area leaking oil looks more like the head gasket at the back of the engine.
A failed gasket can cause oil to leak out of the engine, and/or leak into the cylinders/ water ways. It can also cause coolant/ water to leak in and/or out of the engine. Or a combination of water AND oil leaks depending on where or how bad the gasket has failed. Therefore it doesn't necessarily mean that a failed gasket will cause water leaks, though that is more common.
Head gaskets can simply fail over time, though a common cause is lack of or insufficient coolant/ antifreeze mixture which allows corrosion to occur. This corrosion can eat away the gasket as well as aluminium parts like the head, which is also why anti-freeze is called a 'corrosion inhibitor' as well as coolant.
It's important to make sure the correct antifreeze mixture is used on engines with aluminium heads, and especially the turbo as it helps the engine to run cooler.
Also, it's best to use distilled of de-ionised water and NOT tap water for the cooling system. Tap water contains many impurities which can spead up corrosion!
A head gasket can also fail if the head 'warps'. This normally occurs if the engine has overheated at some point. The head on the turbo I think is made of aluminium, which warps far more easily than cast iron if the engine overheats. When aluminium overheats, it can distort from it's original shape. On a head this can make the mating surface uneven which then means the head won't seal the gasket properly. To rectify a warped head you have to have it skimmed by a machine shop to make the surface flat again, as well as replacing the gasket.
Also, if the head is incorrectly torqued, this can cause it to warp. See the workshop manuals for the correct torque settings and just as importantly the tightening sequence.
If your car is just leaking a bit of oil, it might be worth trying to re-torque the cylinder head bolts. Sometimes that can cure a small leak, though you would be best advised to keep a close eye on the leak areas afterwards.
I don't know with regards to the turbo engine, but some cylinder heads have 'O' rings to seal some of the oil ways. It might be one of these that has gone.
Lastly, a compression test on all cylinders would be worthwhile as this would give a clue to how bad the headgasket might be if it's at fault. Also check the water level and see if it's contaminated with oil, and check the oil level to see if that has any water contamination. Both of these give indication to possible head gasket failure.
All you can do is go through a sequence of checks to isolate the problem, though there's no reason why any of them should be too difficult with the right manual/ instructions and tools.
Let the board know how you get on.
Chas