Drupal module creation to use external Table

Avg Bid (USD)
Project Budget (USD)
$30 - $250

Project Description:
I guess this is just a simple module.
my current database table:
acCard : contain member information and bonus point info
acProduct: contain product information

I want the users of my current acCard table on the server to be able to login into my Drupal site.
I don't want to migrate the current users to Drupal, because I need the same database for different things.
also need the bonus point feature.

I want the product sold in website can select from acProduct table and update its quantity.

Skills required:
Drupal, MySQL, PHP
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