Amazon store script modification

Amazon offers API and when using it you can get same store as Amazon. I have website for very long time which is using CGI script that is using this API. That script is not supported anymore and I am thinking to do some changes as my site is not getting almost any visitors. And I also want extra feature that would give price comparison for all Amazon shops... that is also supported by API but right now I can only switch locales but it does not show directly in which European amazon its cheaper. So I like to see all prices from all amazons if possible. Get SEO done and also some link building which is part of it. There is also shopping cart but right now its not working for some reason, in past it was so i need to fix that also. Its CGI script but if you come with similar script in other language than I might accept it if it has that functionality.