Automotive wordpress theme search update

i need wordpress custom theme upgrade as following: the theme is: [login to view URL] the Manufacturer is not working the way i want it, you can test it in the above mentioned link, the current logic of this theme is it reads a text file and post the content in the secondary search form, so the theme require i write all the car models in a text file like this for toyota cars: <option value="">Select a model</option> <option>Camry</option> <option>Avalon</option> <option>Corolla</option> those options are loaded by javascript: <?php if ($search_manufacturer_level1 != "") { ?> <script type="text/javascript"> $("#manufacturer_level2").load("<?php bloginfo('template_url');?>/secondary_search_manufacturers/<?php echo $search_manufacturer_level1 ?>.txt"); </script> <?php } ?> into <?php if(get_option("wp_secondary_manufacturer") == 'Enable') { ?> <label><?php echo get_option('wp_Heading_Manufacturer_Level2') ?></label> <div id="manufacturer_level2_drop_down"> <select id="manufacturer_level2" name="manufacturer_level2"> </select> </div> and it require to enter the name of the model manually when adding post and it should be identical when adding it to the post through admin panel. by doing so, the following scenarios are going while running the website: 1- if the model entered manually is not matching the one in text file the listing will now appear while searching that model. 2- when selecting a Manufacturer a list of models is displayed even if the model doesn't have any car listed on it. 3- the years are listed even if this model is not produced in that year. so what i want is: 1- adding manufacturers and models control in the admin panel where i can add, delete, edit, set the model start and end years. 2- adding the model in the post should be with radio button or select that shows the models of the current manufacturer. 2- optimize the function in main page by displaying only the models that have an active listings and the years which contains the model. That's it. The budget is limited as noticed, i will pay when you finish the work. and because this theme is a premium theme, i will give you limited access for the required theme files.