I do not see why a not so good GPA would ruin your chances - provided you spread yourself more. Sure, you won't get in at Harvard and/or Berkeley - who do not like people with even one major weakness in overall app - But other univs are ok.
I suggest two things
(a) For PhD - Apply to more univs. There is nothing like a bad PhD as along as you are within top 50 univs. Most good Schools who offer PhD's are pretty serious about that - they better be, it takes too much of a school's resources. Talk to current PhD students, email to profs. I think there is still time to apply.
(b) Did you manage to get strong recos from Profs at IIT/B ? That would be actually important, given GPA. -"Potential to do research". For example, did you excel in a particular project work, BTech project etc - if so, get that reco.
And for MS outside US - look at LSE. Insead has just started its MS in management program, that would also be very good.
And don't worry from the start