First off if I can get a link to the interview that stated that the RE6 takes place 10 years after the Raccoon City Outbreak then what I am about to put forth will be null and void.
After watching the trailer again (for the hundredth time) i realize that the President and Leon are the only people who mention the Raccoon City Incident, but never say anything about the passage of time since. When the President is talking to Leon the conversation itself is a flashback, so we don't know when it took place. If the President is Ashley's father, which would explain why the President always valued his friendship, then he wouldn't be in office more than twice (4 years apiece. 2004-2008/2008-2012 if consecutive terms, or 2004-2008/2012-current if not. However if I recall the time of year is never stated in RE4 other than 2004 so it could be possible that the President was 2000-2004, but I digress.) So the conversation may have been years ago, but after Leon rescued the President's daughter in 2004, if it is President Graham. (Note: some people still refer to past presidents as Mr. President after they leave office so it may be a moot point entirely.) Given the way things are I think if anything the game will take place in two different periods of time, or be after the events of RE5. At this moment in time it is all conjecture.
As to who the "bitch" may be I could go with Ada or Helena, but I think it could be Jessica Sherawat or some other female character introduced in Revelations.