Shopping Cart Migration & Login Development

I'm seeking an expert to migrate the shopping cart from my old website, dropshippii.com, to my new site. The cart needs to be debugged, repaired and optimized for speed. Special attention should be given to the design for mobile devices, adhering to the responsive design principles used by citysocial.com.

Key Responsibilities:
- Integrate and modify the shopping cart from dropshippii.com to the new site
- Debug, repair and optimize the shopping cart for both web and mobile versions
- Ensure mobile shopping cart page is responsive and user-friendly
- Develop a login method exactly like citysocial.com, both for the page version and the pop-up window version

Please note, the shopping cart should be a copy and modification of the original, with the need for an experienced developer who can confidently replicate and adjust the necessary features.

Ideal Skills:
- Expertise in e-commerce website development
- Proficiency in debugging and optimizing web applications
- Strong understanding of responsive design
- Experience replicating and modifying existing web features
- Familiarity with citysocial.com’s design and functionality

Please review the attached images before we discuss further.