Hi, i can do this for you, to implement the filtering / sorting the settings from admin on product page. I can do it in 2 ways, one , the sorting to be made with simple php, and this will generate new links, mean the sorting / filtering will work as category selecting now, Or i can do it with ajax/ javascript, and this will be very user friendly.
Please send me more details about your website, if you are interested on my bid, like platform (build with a framework like codeIgnitor or based on a cms ?), do you have a development server?
My bid is of 255usd, you will pay after the job is done, and everything works smooth. For the timeframe i mentioned to be 7 days, but i expect to finish if the current code is well documented in 3-4 days.