Core Joomla Developer

Hello,I have a website that has already been [login to view URL] am looking for a dedicated joomla developer to customize for me a coupon manager for the [login to view URL] understand that the experience has to be in core Joomla development and not just basic customizations. There are many out there who claim they know Joomla but there're only a handful I have come across so far who actually know Joomla inside out. This job is urgent so I might choose a bidder in the next few hours. Here is the link to my website..[login to view URL]