Complete Unfinished B2B Magento Store using Supplied PSDs / Theme / Spec

B2B Website. Responsive design. The project is half finished due to developer leaving the company. Website has been designed – we will supply all PSD’s but are open to UI/UX feedback. We have based the design on the Infortis Ultimo theme. This is required to be updated to the latest version – we will supply. Currently we are running our test / developer installation on Magento 1.7.0.2. This will need to be upgraded to 1.8 (and 1.8.1.0 in Dec). No changes must be made to Magento default files so that it can be upgraded with limited difficulty. Custom sub theme must be used. All custom content should be easily changed by non-technical users in the back end. Website must be usable in IE8 and above and all other browsers. Various custom code is required. See attachment for all details.