Minor adjustments to post custom fields on a WordPress site

I have a WordPress site built on GeoTheme theme. The site is a place listing directory. The theme uses post custom fields to allow the admin and user to add certain filterable criterias to each place that is added in the site. So when a visitor looks at a certain category, he will see the filters (post custom fields) from that category and has the ability of filtering the results. When adding a new post custom field I have the option of assigning it to a certain category, or even multiple categories. No matter who and how adds a place on the website, these post custom fields are assigned to each place from the front end. When I try to edit a place or add a new one, I can see all the post custom fields, no matter what category I select. So I need someone to make a small tweak (in JavaScript I think, maybe AJAX) so that after I select a category, the site will display only the post custom fields that are assigned to that category. I would prefer this to be done using AJAX so that the page will load the post custom fields instantly, but I am opened to other suggestions. We can also change the order of the fields that appear under the "Add Place" page. I am attaching a screenshot where I made some annotations, things should be pretty clear. But I am happy to answer all your questions. Please write the word "GEOTHEME" in your proposal so that I know you are not a spammer. The work will be done on your computer and when you finish you will send me only the files you changed and I will replace them on the server. Each modification in the files must be properly commented. If you need to delete a part of the original code, DON'T! Just comment the code that you wish to delete and add your own code. I will check by hand the modifications done in the files!