Auction Website UI Overhaul

I need a skilled developer to redesign the user interface of my existing auction website. I'm not looking for a complete build, just a modern, user-friendly interface based on a sample model I will provide.

Key Requirements:
- Improve the current user interface
- Implement user authentication and account management

Ideal Skills & Experience:
- Proven experience in UI/UX design
- Strong portfolio in auction or similar websites
- Expertise in user authentication and account management systems
- Ability to work with existing code and improve rather than rebuild

Please share your previous work examples.