Hello Sir,
I've read your project description carefully, and I understand that you're looking for someone to fix the responsive issues on your website. Such job is daily practice, and I'm confident to say that I can complete this job.
My name is Duc Nguyen, and I'm a Senior Web Developer with more than 5 years experience working with PHP, Twitter Bootstrap, CSS3, HTML5, etc. Also, I'm a fulltime freelancer so I can start the job immediately.
If you have any questions, don't refrain to ask.
Best regards.