The general rule is that bills fall if they are not passed by both Houses by the end of the session, with the exception of bills that have been agreed for 'carry-over' (see Standing Order 80A - http://www.publications.parliament.uk/pa/cm200506/cmstords/416/41604.htm#a90). The session is due to end a few days before the opening of the new session, scheduled this year for November 6th.
Unless of course a General Election is called!
According to the House of Commons website "The (General Election) timetable runs for eighteen days starting with the dissolution of the old Parliament and the issue of writs on day 0 and ends on day 17, polling day. For the purposes of the timetable, weekends and public holidays are disregarded."
If November 1st is to be election day then Day 0 will be Tuesday 9th October! (By tradition polling day is a Thursday - but who knows if Gordon Brown will surprise us with a different election day)
So we await the next few days with interest.