PHP/MySQL Allow webite owner to add items and their images to database , then have that information show on a Wordpress webpage.

I have a website that is already built and I need some PHP/MySQL work done that will work with a Wordpress page. The website is for a mechanic who also does a small amount of Auto Sales. For the Auto Sales part of the business I would like to have created: -- a simple login and logout just for the site owner (1 person). -- an html form that they can enter in the cars they have for sale (multiple details and an image of the car). they also need to be able to update and delete the entries as they go. -- have that information echo'd back on the same page of the form so the site owner can see what they currently have for cars listed for sale. -- lastly have the Wordpress site we have currently create a new div and display the information form the database as the site owner enters the new cars in. So basically I want to set it up so the site owner can enter in their own information about the cars they have for sale and have the site pull from that database and update itself based on what the site owner adds/edits/deletes from the database. I am a web designer but just starting to learn PHP/MySQL. I started doing the work myself and realized I may be in over my head. Thanks in advance and I look forward to working with you.