Add tracking script to Creloaded

Looking for someone who has great experience in tracking conversions. We need to add a tracking script to Creloaded website to know which keywords that comes from Google Adwords make sales etc. It has to be a PHP with MySQL database driven script. We need to discuss which script should be used before installation. ** We already have Google analytic but it is not good and so it needs to be removed from the website p[prior to install the new script. Chosen script will be bought by us, only de-install and installation of script is needed.