Hi,
so every client has it's own VLAN, Broadcast-Domain, Spanning-Tree instance and IP-Subnet?
Is there any special reason for doing so? You can do it this way with a few tens of clients, but it's not very scalable.
Anyway, if you want to monitor the bandwidth consumption on each switchport, you can use freeware RRDtool-frontends like MRTG and Cacti (you have to enable SNMP on your switch). Cacti is very easy to install, you can even find videos on youtube.
Depending on your router's capabilities you can also collect detailed information like IP source and destination, portnumbers, etc. on a per-flow basis when you enable NetFlow. There are also freeware tools but setting up them is not easy. There are also evaluation versions of tools like "Scrutinizer" which allow you to see the last 24 hours.
Hope that helps
Rolf