Episode 4-Huge question

I have ahuge question about episode IV---Darth Vader is Luke and Leia's father, correct?...if this is tryue, why does leia tell Kenobi that HER FATHER is requesting his help? That whole sequence makes no sense...if Vader is her father, why would she tell Kenobi Darth Vader needs his help to destroy the empire?..here is the quote I speak about


Princess Leia : General Kenobi: Years ago, you served my father in the Clone Wars; now he begs you to help him in his struggle against the Empire. I regret that I am unable to present my father's request to you in person; but my ship has fallen under attack and I'm afraid my mission to Alderaan has failed. I've placed information vital to the survival of the rebellion into the memory systems of this R2 unit. My father will know how to retrieve it. You must see this droid safely delivered to him on Alderaan. This is our most desperate hour. Help me, Obi-Wan Kenobi; you're my only hope.

 

Leia is talking about her adoptive father, Bail Organa.

 

The father she is referring to is her foster (or adopted) father, Bail Organa, whom we have seen in the prequel trilogy portrayed by Jimmy Smits.

 

thank you

 

Episode 3 will answer all that

 

He's the dude on Palpatine's high council. He's human, has a black cloak and a short black beard. You see him in the scene where Palpatine's looking down at the clones at the end, plus a few other scenes in Palpatine's office.