Need an Expert on craigslist Clone from xzeroscripts.com

I have a craigslist classified clone website someone built for me. This website have been working fine for over 4 years now. However, from 4 days ago it started running real slow. It now takes about 2 minutes for the front page to load. I did not make any changes to the site or added any thing. Infact I have three websites that is built with the same script. And they are all doing the same thing - takes forever to load. I need someone who understands this script, to figure what is going on and fix it. It has to be something simple. This is craigslist clone. I see it on [login to view URL] To get this project, you must show me that you know this script. None of those generalization will do it. Be specific.