Hey there,
I'm going to make an assumption here and, if I'm wrong, please correct me!
Based on what you wrote (or didn't write - it was a pretty brief profile summary) I'm going to assume you don't have exceptional work experience either. By that I mean, above average leadership or impact. Am I right in that? You also mentioned your extracurriculars are nothing special so that's another thing.
Let me ask you a question - how confident are you in that 30 point improvement? If you haven't got much else to drive differentiation, a great GMAT score can help. A 720 is pretty average for that program - it seems everyone who applies has a killer GMAT.
So, if you're REALLY confident, then go for retaking it and apply R2. If you're not (and you need to be honest here) then apply R1 because if you improve your score 10 points that won't make up for the advantage lost between R1 and R2.
Bhavik