Hi Tom,
I've reviewed your project details and your website (as least as much as possible without actually buying a card) and I can see why you want to make some enhancements. I do believe that moving to Ajax would be the best solution and would provide the most flexibility for you moving forward. You also mentioned the search engines and my quick review of some of pages on your site revealed some basic issues which likely are hindering your placement in the search engines somewhat and we can resolve those as well.
My bid amount and time frame for completion are based solely on what I can see, however I hope you can understand that without see the raw code behind the scenes its very hard to determine exactly how long the work will take. I actually would expect that the project wouldn't take as long as I've indicated.
I'm sure you have and will receive bids which are lower, and I hope you'll consider the skill and experience that goes with the bids when making your selection. I have been programming for over 25 years, with the past 15 working with Internet technologies. I've been working with PHP since version 3, and working with HTML since its inception. I work with customers from around the world so I'm very flexible in my availability, I can be available to discuss you project at a time that works for you.
If you would like to further discuss your project, I'm available at your convenience. If you have any questions, please don't hesitate to ask.
Regards,
John