Hello,
I seeeee. Well, for your school choice, you can definitely apply to Wharton, Kellogg, Columbia. But they are a bit of stretch for you given your GMAT. Which means that if your intention is to absolutely get in THIS year so as to make things easier because as you wrote, anyhow you were obliged to leave your job, the wisest thing would be to add some Second Tier schools in which you would be more competitive, and even a school or two which would be "Safe schools". The reasoning being, that if you are banking on getting in and aren't looking for a job, you don;t want a nasty surprise at the end of the season, and you want to cover all eventualities.
As for Oxford v. LBS, although yes, Oxford is a more famous university, LBS turns up higher ranked for its MBA program than Oxford, and has better international prestige (although don;t get me wrong, Oxford is a wonderful program!)