Assistance Removing Malware from site

I need assistance and direction removing malware hack of quincymusictheatre.org. The site was flagged by Google a month ago. We completed the clean-up process as defined by Google. Was approved and thought issues were resolved. Added additional security, to include changing login requirements and site lockout based on failed login attempts.
Today, visited the site, and the home page was littered with malware links, most referencing casinos.
Did a temporary switch to change the homepage for another page not currently affected, but need a permanent fix.
I've researched various options through the Internet, but there are lots of opinions out there... I trust you guys more.
Thanks in advance for any help!