Hi Niti
Unfortuntately I can't really say on US colleges but your UK list looks about right - possibly with the addition of Oxford. If you wanted to consider other UK School then possibly Essex, Nottingham or Bristol may be of interest. I can't really give any indication as to how difficult it is to gain entry to their programmes.
As to your grades, your BA score is competitive however the selectors with pay particular attention to the School you studied at. For the MSc Economics and Management programme I'm afraid that your GRE quant score is possibly too low. Unfortunately this may diminish your changes as generally the selectors will be looking a GRE quant score slightly higher than this. They are usually not too concerned with a relatively low verbal score. The GRE score is but one factor and they will look at your complete application so it is not possible to give you a definite indication. Hope you understand.
James