Classified website modification (PHP, Ajax expert)

It is a just a single modification right now....But need many changes in site..after reviewing your work I have classified website using a smarty template engine theme. Currently ad posting method is based on 7 steps that is very lengthy process for a user... 1> Chose category 2> Chose plane 3> Enter Detail 4> Upload photos 5> Some features options 6> Review Ad 7> Publish Ad I want it to be single step via ajax. Example is [login to view URL] . Actually i want same criteria for selecting category as above, when category selected then automatically second step should appear, when second step selected then 3rd step should appear... in 3rd step all of other next steps should appear....i will give you example if you are unable to understand... Only experienced developer needed for long term work. Must have knowledge and experience in PHP, mysql, Smarty, Ajax