Joomla Site Injections - Clean and Remove NO UPGRADES

I've got a custom website that's running an older version of Joomla. Yes I am aware that outdated scripts can lead to the types of problems I am experiencing now, however the site has lots of custom modifications and we are working on a completely new site. So... what I need is for someone to clean my website and remove the injected code properly. I will not pay until it's clean and passes a scan. All pages and functions must be working as they were before to consider the project successful. I look forward to your bids. $30-35 range!