Postgraduate Economics: From Warwick to Cambridge, Oxford, LSE, Harvard, etc.???

Hello everyone,
I have a question regarding my chances for postgraduate studies in economics. I am currently an economics undergraduate student at the University of Warwick and am now considering postgraduate study in economics towards a PhD. My question is whether I have any chances to get into the top schools for economics.
Firstly, is Warwick reputable enough for getting into those schools?
I am asking because I am originally from Germany and Warwick was my last choice after I did not get into LSE and Cambridge. That was really devastating because I did actually get a 1.0 GPA in my German Abitur (equivalent to IB 42-45) including 14 points in advanced mathematics (equivalent to 7 points in IB). However, as my teachers were quite unexperienced, my predicted grades were really low. Thus I got rejected by the schools because "my PREDICTED grades lied below their standards".
I have finished my first year with a first, but a low one (only 73). This was also because I was never taught entirely in english before, making the contexts much more difficult to grasp. Now that I am in my second year I am really sure that I will be able to score in the high 70s. However, even if I am able to do that, do I have any chances to get into Cambridge, Oxford or LSE for a MRes. How about from Warwick into top US schools like Harvard, MIT or Princeton for a PhD program?

(I am already working on getting research experience and consider taking the LSE summer school course in Real Analysis)


Thanks