this week at my venue there is a 800 point unrestrickted event and i no there will be a dark pheonix bi atleast 2 or 3 people.So what should i do?

The 3 P's Probably work best;

Pulsewave
Probability Control
Perplex

Off the top of my head i'm thinking Nimrod or Braniac or both along with some TK and maybe a medic?

V Icons Superman + 3 perplexers and someone with TK can deal 8 damage to her very easily. Use Disbanded to take away her Power Cosmic. She can't see through stealth, so use that to your advantage. Mystics, Crossgen, and wildcards to copy them are also good ideas. Psychic blast and Pulse Wave are always good. If you play Disbanded, you can Outwit her too. She's actually very easy to beat, unless she gets her Impervious rolls. She's extremely reliant on those. Have Superman hit her for 8, so she only gets to try to roll out one time.