Back Office Product Management create/update/delete products) for a Magento E-commerce store

Thank you for looking at this project. I need someone familiar with Magento shopping cart to help with backoffice tasks. My products and catalog is not up to date. I need someone to go over all product lines and add/remove/update products accordingly. You will need to update the products from various manufacturers by looking at spreadsheets, manufacturer's site, competitor's site, etc. You will need to update attributes (size, colors, etc.) or prices/images/pictures/ etc. Please assume that there are ~ 500 products and bid accordingly. Not all products need to be updated. I would guess* that there are 250 products that need to be updated and around 100 new/to be added. The rest should be cleaned up/deleted. Please tell me what you are basing your bid on. Please also let me know how long you think it will take to finish. **All deadlines are strictly enforced. If you cannot adhere to the timelines DO NOT BID. Also, please provide a bid... bids with no amount will be ignored and reported.** You need to have had experience with Magento. Please do not ask me: "How do I do this in Magento" If your score is less than 9 please do not bid Thank you