WordPress Theme Customization Help

I'm building a WordPress website and need assistance to complete it. The main issue I'm facing is with the design and layout, specifically with theme customization.

I'm looking for help with:
- Customizing the header and footer design

Ideal skills and experience:
- Proficiency in WordPress
- Strong background in theme customization
- Experience with header and footer design modifications
- Knowledge of responsive design principles

Please provide examples of previous work and an estimated timeline for completion.