Network Engineer specializing in network security(2)

Network Engineer specializing in network security iframe virus on my website I have clean up and upload all the new file and update all already for my site . But just need to know how to prevent it for happen again . because after I have update all .. sometime one month or few week later it come again ...... So can give me advise And I have same problem about 4 time already in about 5 - 6 month . Need to clean , clear and prevent Infected in future . Please check and help to made sure no one can deface my website. Please also test my website security for XSS and other common scripting vulnerabilities and detailed report of the assessment including any weakness I find and how to fix them . 1 have a website that is heavily infected with malware and has thus been removed by Google. I need this to be solved as soon as possible. This is a complex job, with no backup of the original website, so please make sure you are confident that you can successfully complete this job . someone who can protect my website from hackers by reviewing the code and implement the fixes/preventions at the Code level. need to check 4 sql database also . because maybe is database in the sql have infected also .. and the script . Need to clean and fix all problem . Now i have just remove all the inflected iframe code that is inflected and injection into it .