Monitor and manage small broadband link

Hi all,
Recently my company setup a broadband link external to all enterprise network. This is a simple ISP connection they pay for separate. Business reason justify such installation.

Now they have expanded this link to a small lan. and got it wireless. Because these now accommodates more than 1 user they ask me to look after. But I have no clue how should I manage bandwidth and control who uses the resources…

The design is ISP modem Linksys router Cisco Switch Catalyst 2960 C Series 4 Wireless APs. The Cisco Switch also has a port connected to a Cisco 2500 Series Wireless controller.

I have been exploring the capabilities of this wireless controller but I get only general statistics about traffic… I can not see if what each IP is using from the bandwidth and for what is it using..
Because I have no servers or firewalls in the middle I am a bit loss on how to administer this…

Any one with similar experience?
Many thanks