Add-On to existing Classified Ads Script!

I own a site which is currently under construction. It is a classified ad business directory. The one thing it lacks however is the ability to allow a visitor looking for a business in their area to query by State, County or City which I would like added. The following is a link to this script. If you are familiar with it, please provide your best bid to add onto the script the ability for a user to easily choose to view either everything on the site, or to choose by these simple three criteria again of State, County or City. This obviously meaning, it would only show results to these areas if available. The script was built for our use and a proprietary statement of non-disclosure would be required (meaning, this script once modified may not be used to resell in it's original or modified state from building off it's script framework if someone were to ask). So bid away, this should be an easy one! I need three (3) extra fields to query my data. 1. State 2. County 3. City PM all questions to me here on GAF. Thanks!