To be honest, i dont think theres a final patch coming. Would be good if BIS did one last patch for this game. Theres still a lot of people playing and in many ways I prefer Arma1.
Well done on completing the mission without the mods, give it a go with durgs fix as well, it does make it more enjoyable.
I finally managed to pass this by running to the middle, laying down, ordering guys in line formation, ordering to stealth and started shooting. Luckily the other guys were THEN well enough positioned to shoot the intruders..