I can't find a daedric helm anywhere is it even possible to get one on PS3?

First of all, are you level 21? That's when they start spawning.

Marauder warlords will have a higher chance of having one then generic marauders. A famous way of getting a Daedric helm is to go to the Roxey Inn, where a woman named Rigmor will be equipped with one. (After level 21, of course.) If you drop her disposition to 0, she'll attack you so it won't be a crime to kill her and take her helm.

I'm lvl 27 and is she needed for any quest? But thanks.

http://www.uesp.net/wiki/Oblivion:Rigmor

Technically, yes. But it won't damage anything if you kill her. You'll essentially just "skip" the part where she and her gang are supposed to ambush you. Not a huge deal. If you don't want to skip that, do the quest.

These are really hard to find. There will come a point though, where you will have many. I suggest not skipping the ambush. It's a tough battle, and they have fantastic loot at high level. Archers should definitely walk into the ambush, as one of your enemies has an amazing amount of enchanted arrows, topped only by that one Daedric Quest, can't remember the name at the moment.

Is the daedric helm as good as the helm of Oreyn Bearclaw? (without enchantments)

Check the Maruarder Forts the Warlords might have a Daedric Helm
You could also check the monster dungeons or Oblivion Gates

There are - for some strange reasons - no daedric helmets to be found in the Oblivion Gates. No gauntlets either (except in these 'gore-bags' if you'r lucky).

The Marauder Forts is your best bet. Fort Blueblood, SE of Leyawiin, for example. I found alot of Daedric-stuff there. Fort Wooden Hand is another good place to search. Save your game before entering the chamber with the Warlord, kill him, and reload if he dosen't wear what you need.