Guild Wars 2

Is there a backpiece with Power, crit damage and vitality if so please help me by telling me what it is and where I could find it, thanks

Those are Valkyrie stats. You can get that from the new Advanced Spinal Blades back item. That one is exotic. The ascended Tempered Spinal Blades only has Berserker/Valkyrie.

The stat combination you are looking for is Valkyrie. According to dulfy.net you can choose Valkyrie stats on the exotic version of the new Spinal Blade back item. But apparently the ascended version only allows Berserker stats + Valkyrie upgrade. Light of Dwayna and Shadow of Grenth also only allow for the mix of Berserker/Valkyrie.

Thanks for the help