Questions about setting up a Wireless Access Point

I want to set up a wireless access point so I can provide free internet access to my customers.

This is my network topology. I have about 6 computers, an ADSL router and the wireless AP hooked on a 16-port switch. There are shared folders between the computers that I do not want out in the open, so I have to somehow restrict the AP to connect only to the router and not the rest of the network.

Also, since the AP won’t have any password protection, I want to do something about leechers. Is there any way to restrict the maximum bandwidth used by the AP?

You need a clever ADSL router - something with a VLAN (to stop visitors dropping in on your network) and QOS (to manage bandwidth) - how about this:

http://www.draytek.co.uk/products/vigor2700.html

Apologies - on reflection this is a better choice:
http://www.draytek.co.uk/products/vigor2910.html