hotspot billing software

[ike.ubuntu]

i run an internet cafe & have decided to use ubuntu server as my proxy. All other computers in d LAN (including network users' wi-fi enabled notebooks) run on windows. I am looking for network hotspot billing software that will run on ubuntu server without the need to install a client version on other computers accessing the internet via the proxy. pls can anyone recommend a network (both wired & unwired) hotspot billing software that is compatible with ubuntu server. I dont mind if i have to buy it.

Thanks