right then........100% the head gasket..
i would recommend you skim the head they do warp a little if overheated.
you can reuse the bolts,
you should also change the thermostat,
the water pump will be ok,(they rarely fail)
change the timing belt as well,even if you dont and it breaks it WONT bend valves,
i wouldnt use a non-genuine gasket set for the simple reason ive had them fail all to often a genuine set will be about £35.
all you need is a 10mm spanner and socket and 13mm spanner and socket for the whole job there so easy.
you can leave on the inlet manifold just unplug the injector unit.
undo the exhaust manifold whip off the timing belt,rocker cover,head bolts and its off.!
i can get a head off in 17mins.!!!