Need help with simple sip extention rule

hi all ,
i want to to create a sip extention with quoara of time

as an example , i want to set a quoate for that extgention to call only 5 minutes on a specific trunk.
how could i dont that ??

ive installed a2billling but i need you help how do achive my needs ?
how will frepbx help me ? or how will both of freepbx and a2billing will help me?

regards

Trunk balancing module