Please note, my bid is for one page (or series of linked pages, as in a form and a processor) as you aren't specific as to what the 'script' is (is it one page? a whole site?). I just went through a similar situation and am well versed in prevention techniques with Classic ASP/MSSQL now as well as familiar with HackerSafe and the likes, should you have access to these tools.
US native, paypal preferred.
Note:
If this site is in .Net, please disregard my bid.