Magento product data manipulation and upload

General information for the website: Fancy dress website Description of requirements/features: We need our suppliers CSV manipulated to fit into our Magento site. This will require editing the CSV so that once uploaded (via Rapidflow) to our site, it is ready to roll out onto Amazon/eBay etc. All images should be edited so that they fit with the minimum requirements of Amazon/eBay and display correctly on our site. The Configurable and simples will need to be setup correctly (sizes) to match what we currently have on our site. This will be something we need doing on a monthly basis. *IMPORTANT*IMPORTANT*IMPORTANT*IMPORTANT* Please only respond if adding products to a Magento site is something you have done many times before, we have had timewasters in the past who want to learn whilst trying to do this job, experts only please. Specific technologies required: Magento, Excel, Photoshop Extra notes: magento Version 1.9.0.1 (fully patched) Server is on Magestack (dedicated) Current database includes over 40K products Over 18K in stock at any one time