Shopify Store Refine & Fulfillment Integration

I need an experienced Shopify developer to refine my existing store for four editions of the same book and integrate with a fulfillment center including Amazon, possibly Huboo/Gardners. Also need to integrate a variety of payment systems... (Budget: £250 - £750 GBP, Jobs: Payment Gateway Integration, Payment Processing, Product Descriptions, Shopify Development, Shopify Templates, Website Design)