Testing, debug, enhance existing PHP software that uses Amazon and other store API's

I have some existing web software that cross checks online store prices against Amazon prices and exports a CSV - the software is good but periodically has issues. I need someone to be able to test / debug / add to the functionality of the software. You will be working in conjunction with another developer. Things such as 'save xpath links' are currently being added, as well as adding sites - I want some onsite instructions, and ultimately I want to roll this over to a executable desktop software and I am advertising for this now. For example today the site is not saving data for cron jobs properly - I need to be able to find out why? Things like increasing the speed / automation of the software / etc. Suggestions from you on enhancements are good too. This will be moreso an hourly arrangement rather than a new job.