Search Fields Moved

Hello, I have a classifieds site that I am running and it needs to have one simple modification completed. My site is setup with categories and subcategories. There is also an 'Advanced Search' section. The 'Advanced Search' page contains search fields that allow users to search through the different categories and subcategories of the site. When searching on the 'Advanced Search' page you must first select the category/subcategory you want to search from using a drop down box. Once you have selected the category/subcategory then specific/custom search fields appear for that category/subcategory. I want to move these search fields (code) so it will be displayed within each individual category and subcategory. I also want to make it so the drop down box that shows the category/subcategory is already defaulted to the correct selection. For example, if you go into Category 1 of the site, then the search fields (code) should already be set to Category 1. If you go into Category 5, then the search fields (code) should already be set to Category 5. This will allow for the specific/custom fields to be shown correctly for the category/subcategory that has been selected. I don't think this will be too hard a person that has done this type of work before. I would like to get this started ASAP! Thanks, BCBC