If they really want to make Brie a star, then yeah, just put her over Stephanie tonight by having her force Stephanie to tap out to the Yes Lock (a pinfall victory would also suffice.) Not a single soul would care much for Brie getting revenge on her "evil" sister for turning on her, although it'd probably be seen as a SHOCKING SWERVE by some of the folks over at WWE Headquarters.
Then again, if I were booking the match, I might book Stephanie to win on a reverse decision. Basically, have Brie force Stephanie to tap out like a bitch to the Yes Lock, but then have Brie keep the hold locked on for a few minutes even after the match is over, and the referee eventually reverses the decision and awards Stephanie the victory, even though everyone knows Brie was the real victor. They've done this finish a few times before, most notably between Bret Hart and Jerry Lawler at the '93 Summerslam. Lawler made it personal by running down the Hart Family (just as Steph tried to poison Brie's marriage on Raw last week), so Bret kept the Sharpshooter locked on for several minutes as punishment even after Lawler submitted and Bret's victory was reversed and awarded to Lawler instead (by disqualification), but everyone knew who the real "winner" was.
They could even have HHH come out and order Brie to be carried out in handcuffs again, which I'm pretty sure would be accompanied by a unison of YES chants as Brie was being lead out with a smile on her face.