It's pretty obvious to me she's alive. The plastic wasn't tightly wrapped around her, let alone her face, so breathing under very lightly pile dirt shouldn't be a problem for the short amount of time she'll need.
I also am certain that she knows Tony is in it with Jack (for better or worse), which means she'll probably be the one going to the President directly (since no one else can be trusted thanks to the FBI mole). Henceforth, Jack, Tony, et al end up in the White House at some point explaining away what they did/are doing and why. I haven't seen that preview, but supposedly someone did.
I liked the episode. Especially concerning the Prime Minister and his wife in the safe room. He was willing to die and let his wife die for his country. She wasn't. Safe to say that relationship is probably over now.
10-1 Bill goes out of the office soon to tear it up 'against' Tony and Jack's crew. Bill needs to go back into the field so that he can be the 'one of these people won't make it past the next hour' options. Everyone likes Bill. Everyone LOVED President David Palmer, and looked what happened to him!