firewall - How to limit data usage of individual apps?

There are many apps out there to limit data usage of entire system. Using Firewall, I can block an app from accessing Internet, too.

But, I don't want these. I want to limit data usage of individual apps. e.g. - AppX should be firewalled if it comsumes 1GB within a day or month etc.

How can I achieve this?

I am rooted on ICS. I have tried to use Tasker but without luck.

Answer

I found this app "Onavo". I did not try it but maybe you want to ;)
I read that you can set the limit in the data usage settings.
But i don't find the settings, maybe because I use stock rom.

Hope this answer could help you.