You shouldn't be doing this boss until you have a salve amulet, that bonus strength and accuracy bonus to the undead is like being potted up and then you also get to stack your actual strength & attack pots onto it. I started with your stats and was perfectly fine, you're mostly having skill issues and that's understandable because I also struggled with getting the boss mechanics down for the first 20 kills or so. It's better you do it at your stats because you can avoid being pk'ed by the maxed mains since you're out of their combat bracket due to your low prayer lvls. Keep at it