Website redesign/backend web application building

We currently have a well built operational corporate website. However we would like a complete makeover to the website front-end and especially back-end to meet our growing client demands. Front-end of the website does not need so much work however we need a completely new back-end for it to accommodate a web application that will allow us to manage our customers bookings, course management, e-learning portal etc. Also the back-end should include an advanced control management system for the front end.
Minor SEO work including meta-tagging will also be required as part of the job. More information will be provided to successful bidders.