Help setting up mini wireless isp

Im living in a college of about 10 students all have separate phone lines with 56k dialup.

I have a Netgear WGT634U
http://www.netgear.com/products/details/WGT634U.php
and my customers have
Netgear WG511T 108 Mbps PCMCIA cards
The router is connected to a Speedtouch 500 ADSL gateway.
Im connected to the Router by an onboard network port 100/1000 (Abit IC7-MAX3)

Ive successfully connected myown computer to the net through the router and 1 customer through a wireless card (WG511T)

Im in Australia using Telstra Bigpond 1500/256 kbps 10gig per month plan (after 10 gig it caps speeds to 64kbps)

I want to setup a mini wireless isp so I can cap my customers download speed and limit ~ eg. 10 users are surfing, one user reaches his account limit of 1 gig (per month), he is then capped to 64kbps (or any other amount I choose), other users continue surfing uncapped untill they reach there limit.

If possible I would like to act like an ISP, eg send bills by email automatically and send email notices once they reach there limit.