For your Imperial conversion issue, there isn't any standard scale that you can use. But i suggest you use the "UK honours categories", in your case i suppose it's First class honours.
If this is insufficient for some of the universities you're applying to, get an academic equivalency evalutation with a US equivalent GPA.
Concerning Baruch, keep in mind that the Brand name isn't that powerful from an international perspective. Meaning that it's not a good idea to apply there if you're betting on an international career.