select search form php/mysql

We have a form with 3 select boxes, the select boxes are populated from a mysql database. [login to view URL] This form needs to post to a page using the smarty template system (.tpl, [login to view URL]). Right now it's passing the wrong variables. We need the form to pass the right variables: If the user chooses a year and clicks submit, the query returns that year. If the user chooses a year and a model, the query returns that year and model. If the user chooses a year, model, make, the query should return those results. Ideally we would like a custom message and link to a different file if there weren't any relevant results. I also need the form to work as an include within a .tpl file (CS-CART, [login to view URL]) on the side-bar. Please do not bid on this project, if you do not understand it. PM with questions, thanks.