Drupal Expert for Community Site Enhancement

In need of an experienced Drupal professional to fix bugs and enhance an existing community site. The ideal candidate should excel in the following areas:

- Drupal theme development
- Drupal module development
- Drupal site administration

The main task is to refine our existing site by adding new functionalities and fixing some bugs. I'm specifically looking for someone who can -

- Incorporate a private messaging functionality
- Set up an online forum/discussion board
- Refine the user registration and login process

A background in enhancing community/membership websites is necessary. Having a portfolio showcasing relevant projects completed would be beneficial.