I can suggest Manage Engine Firewall Analyzer, its a pretty useful software. I think it does not need to be logged in with admin rights etc, it runs on IIS.
Your second option is, if you have adequate model of Cisco Firewall and memory, you can upgrade your IOS to 8.x and ASDM to 6.x, which has a built-in option of monitoring top 10 services that includes the bandwidth utilization.
The best solution to this problem is to use Fireplotter Software (around $400 US). It shows and plots all connections going thru the ASA and you can sort via TOP talkers/protocols/bandwidth/etc.. Cisco should really buy this product and merge it into the ASDM.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...