Managing user acces on Oracle

Hi,
I need a solution for the following. First let me state that I'm pretty clue-less on Oracle.

We have Oracle database (8.1.7 Enterprise on AIX). Our intranet website pulls it's data from this database (Coldfusion). We also have an inhouse application written in delphi wich uses this database. Accounts are stored in tables in the database. Based on the account, certain access is granted or denied (both on the website as in the application).

But now we want to make some information available to our customers. However, we need to make sure that customers only can see their own stuff, and that nobody else can get into this system. In order to do that, we could continue to use the same idea, but there are some drawbacks.
Specifically, I want to have a full blown user account management tool. Accounts should have password aging, intruder lockouts etc. For a particular part of the customer site, I even want to use a one-time psasword system. Preferably without tearing the whole database apart and building it from scratch..:)

Do you know of any solutions? All hints, tips, knowledge is *greatly* appriciated!
Tia,

-- 
Jeroen