First:
Check that the oil leak is in the valve cover and not from the cylinder head. If it's from the cylinder head, even if the seller is going to do repairs, ask for a bigger discount. If it's the valve cover, it's no big thing.
Second:
Please
don't post so many threads about the same problem. Post
only the pictures relevant to your problem.
Sobrang laki ang pics mo, p're. Some of the people who can help you are on dial-up internet only, at matagal mag-load... I've been waiting ten minutes at di ko pa makita yung pic ng leak!
Third:
Check out
www.nissanbayan.com and register at their forum boards. gasket leaks on older Cefiros are very common, and they can give you some good advice about them. Use the search function and look for "Cefiro gasket leak" to point you at relevant topics.
Good luck!
EDIT: Kita ko na... mukha ngang valve cover lang.

Pero best bring a mechanic along for the second viewing, to be sure.