What skills are you looking to improve on? HTML & CSS? Maybe a server-side language?
Once you take a basic look at DW that's all you need for awhile. It would be more worth your time to learn about HTML and CSS and then move onto server-side languages. First thing that comes to mind for structured lessons are www.lynda.com . But there are a lot of other tutorials online about the subject, some you don't have to pay for. All depends on what you are looking for.
Assuming you're on a Linux/Apache server, you need a database (MySql) which stores content. And server-side scripts (PHP) to poplate pages with content from the database.
BUILDING DYNAMIC SITES IN DW
Get one of the following local testing servers for your OS and follow the installation instructions.
WAMP for Windows
XAMPP for Windows
XAMPP for Mac
MAMP for Mac
Setting up a PHP environment in Dreamweaver
Building your first dynamic website – Part 1: Setting up your site and database connection
If you're not thoroughly comfortable with server-side programming yet, use WordPress to build your site and add a Classified Ads Plugin:
Alt-Web Design & Publishing
Web | Graphics | Print | Media Specialists