Clean up and secure very old PHP script to run PHP 5.4

I have a VERY old PHP script and MySQL DB that runs one of my websites. It was written when PHP first came out (around year 2000). I believe it was written in version 3.0 or 4.0. It has been changed and modified over the years to accommodate PHP changes, but it has some major security holes and will not run on newer hosting solutions. The script is basically in one config file and it has several small files for the header, footer and sidebar that call this main config file. I need someone to go through this file and check it from TOP to BOTTOM and make the necessary changes to make it compliant with at least PHP 5.4. This may mean that some of the MySQL DB info will need to be changed as well. When I try to run the script on newer hosting solutions I am receiving a lot of errors and the script does not function correctly. I can not spend a lot of money on this script because it needs to be replaced. I need to just make it so that it will run on a new hosting server that I have. I do not need any design work, this is all PHP code work. I can possibly give you access to my current server if needed. For this project I need someone with the following: - high rating on Freelancer - someone with good communication skills - someone that can complete this in less than 7 days New, unrated coders, please do not bid! I only need experienced coder for this job! I will make a selection quickly because I need to get started right away.