Help finishing my first tau match

Giant map and slow research. I wiped out the alliance of all 4 imperials, and the two-necron team. The rest died to other ai. Currently its just me and the ork player left and hes rolling out so many gorkanauts and squiggoths that I cant seem to kill. It takes a whole group like ten units multiple turns. I tried firing on them with 4 stormsurges and didnt do that much damage.

What do I have that can actually hurt them? I can only have 2 or 3 superheavy bombers up at once. The seekers do good damage but the recharge is too slow to kill them fast enough.