Uros, I myself would do no more at this juncture than run it for several hundred miles - obviously checking the leakage at nuts and header tank frequently, it may well stop. If it's going to seal itself - it will stop much quicker if you drain the coolant and run it on
plain water during that period but avoid heavy load as absence of antifreeze/water-wetter will upset the heat transfer in the head (ie: cause nucleate boiling written about elsewhere on the site recently by me). The modest corrosion that sets in may well 'do the trick' quicker.
If that shows no sign of working get hold of some 'Bars Leak' and put that in the cooling system. See:
http://www.barsproducts.com/barsleaks_products.htm
If that doesn't work - the thing will need to have the head taken off again and then I would be for sealing the studs into the block at point of propagation of the leakage in the top 4 threads with Loctite Hydraulic seal. Don't use Studlock or you'll never get them out again. Do not lubricate the studs themselves, first put copper-based anti-seize in the lower section of the female threads in the block and Loctite the top threads after. The Loctite will climb up the studs so be sure to wipe the block face clean after. The chance of sealing now at the nut end when it's all wetted as it is now, pretty well zero.
Hope this helps, I have exp this and seen it stop, albeit not with studs. And yes, the ex header top 2 studs need to fixed at low torque - about 4-5 lbf ft and with Loctite Studlock which has high holding strength. Often the nuts (14lbf ft) get overtightened and if that happens it doesn't matter how you fix the studs. Ideally there you want a stud with at least 12mm of thread engagement at the head end.
G