Warwick has an exchange program with UT Austin, which would be a good chance for you.
For example, last year, a girl from Warwick got a decent full-time offer from Dell China when she was in the exchange program with UT Austin. You know, Dell's headquarter is located in Austin.
As it's so hard for an international student to find a job in UK, I don't think staying in the school with better location in UK would help much. So my suggestion would be to find the school who has better exchange programs with top US bschools.