I'm a nord and I started the companions quest and became a werewolf now I'm wondering if I can be a vampire too with out losing my wearwolf power??????

No, at least not without mods. But I own the 360 version + all DLC.

You can be cured of the Werewolf curse. This can be done via the Companions.

Infact if you do the Dawnguard quest, I'm pretty sure the Master Vampire can rid you of it if you decide to join him.

As a werewolf you're immune to disease, so you can't contract regular vampirism. If you have Dawnguard, you can become a Vampire Lord and it will automatically cure your lycanthropy. Also with Dawnguard, you can regain lycanthropy after you cure it - but only once.

No idea if it actually works, but Yahoo answers has this description :

http://answers.yahoo.com/question/index?qid=20130527230953AAgDuw2

Also this might be worth reading :

http://www.uesp.net/wiki/Skyrim_talk:Werewolf/Archive_2#Vampire.2FWerewolf_hybrid (Middle bit has comments on the drawbacks of being a hybrid).