I have a website Perth laminate flooring and accessories online store Built in flash this is first in Google search for most of my keywords

Over the last two months I have rebuilt it in (Wix HTML) which apparently uses ajax Technology I have parked it at www.pertpaintings.com.au to check and made it unavailable to search engines

My worry is will I lose my search rank if I do this
as my Keywords seem to be not relevant to the site anymore and ajax seems to have a bad rep. for SEO

If I go ahead anyway and it does lose rank will changing back to the original site get us back to where we were ?

I would appreciate any help
Regards
John