Hi,
Welcome to the Forums, and I'd like to wish you good luck with your venture into the field.
I think you have made the right decision, when it comes to choosing PHP and MySQL, as these are the weapon of choice for a wide community of develepers around the world, giving you lots of much needed support on the web.
Your solution, seems to be a little bespoke for an out of the box solution like drupal. No doubt that it could be kind of moulded using an array of plugins, but I'd guess you'd perhaps be looking to developing this from scratch.
I would start by following a few tutorials to give you a basic understanding of how things work, and maybe follow a recommended book into the depths of database driven applications.
Be aware, that this project will be big, and will require a lot of work, so start off small, and look to phase in functionality as your confidence and ability progresses.
Failing this, you might want to look for a purpose built "directory script", but I'm sure anything decent would be reflected in its cost.
Good look again!