Build a multi vendor e commerce website

MyArtbay functional requirements ([login to view URL]) MyArtBay is intended to be an art ecommerce website where users can sell and/or buy art, sculptures, handmade jewelry etc. MyArtBay is currently built on Magento community edition along with an art theme installed from gala gallery ([login to view URL]). This website has only test data and all the functions are not tested fully. Functional Requirements: I would like to include more functionality to this website similar to the module [login to view URL] 1. This website needs to be converted to a multi vendor website. Users registered should be able to sell only paintings, sculptures and handmade jewelry. All users registered should be able to buy from multiple vendors. The design of website to be updated. 2. The information required to be collected on a product when uploaded to sell will be the same as in the module stated above with additional fields a) Product size which will be a dropdown list of values (width & height as separate fields) b) Product type which will be a dropdown list of values such as Acrylic, Charcoal, Oil, Water colour, Sculpture, Jewelry, Drawing, Photography and Textile. c) Seller Location Country, State and Postcode. d) Colours used in painting (Multiple select box with primary colours) Changes to the current fields would be: a) The current product category in the above stated module needs to be revised to differentiate Category and Subcategory. The Subcategory displayed will be hierarchically dependent on the Category selected. b) The ‘shipping amount’ field to be updated to include international postage charges and another field to include local postage charges. c) A new field ‘More information on shipping’ will be a description field with the wiz wig editor to provide more information about shipping charges. This information along with the international and local postage charges will then be displayed as a separate tab on product description page along with the three tabs ‘Product description’, ‘We also recommend’ and ‘product tags’. Please refer to [login to view URL] d) The ‘’shipping type’ field to be removed. 3. All the product information fields should be correlated to the Magento admin fields as well at the Magento back end. 4. The response of website now is slow. Loading time required is very high and not acceptable. The user experience of maneuvering through the website needs to be significantly improved. 5. All the other features from the above stated Magento extension needs to be retained. 6. Search functionality: The Advanced search and Layered Navigation search on the left of the website page should consists of • Category(drop down box), • Subcategory(drop down box – values listed will be in accordance to the category selected), • Price Range (Slider ranging from 0 to $30,000 and above). Similar to shown below • Colour with the colour swatches, • Product type (drop down box), • Size (drop down box with values – Under 50cm, 50cm to 100cm, 100cm to 150cm, 150cm to 200cm and Above 200cm.) • Seller Location (country:drop down box, state:dropdownbox) 7. Payment module to be included Recommendation: The Magento extension marketplace ([login to view URL] ) can be purchased if required and or you may suggest any alternatives.