E-Commerce Site Upgrade Assistance

I run an online store and feel the current experience could be much stronger. Because the business lives entirely in the e-commerce space, every click matters, so I’m looking to refine the site from the ground up—visual appeal, navigation flow, load speed, and, ultimately, conversion rate... (Budget: $15 - $25 USD, Jobs: Conversion Rate Optimization, eCommerce, HTML, Shopping Cart Integration, UI / User Interface, User Experience Research, Web Development, Website Design)