I'd have a look on this forum regarding this topic. It has been reviewed and commented several times.
Generally speaking, business schools do not need to have your marks translated into GPA system, since they are familiarized with many mark systems.
mates, please visit my profile and leave comments
I'm not linked to GMAT questions anymore, so, if you need something, please PM me
I'm already focused on my application package
My experience in my second attempt
My experience in my third attempt