malware cleaning of my domain

I am in need of assistance to clean a malware infection on my domain. I have taken measures to backup my website, which is built on the Joomla platform, however, I don't know how the malware was originally introduced. I am looking for a freelancer to help me clean the malware and make sure that the infection has been completely removed. The deliverable should include a report from a security scan that states the domain is clean of any malware. Any suggestions on how to prevent malware infiltration in the future would also be greatly appreciated.