I run a web hosting service and have extensive malware removal experience. I can clean, upgrade and secure your site against reinfection. The proof will be in the pudding, since your site will stay clean, as long as you keep Wordpress and plugins up to date.
I will need up-to-date zips of any commercial software used on the site (theme/plugins). If the site is very far behind on updates, updating all the software may cause site glitches that will need a developer. My job is to remove the malware and secure the site.
All my work is guaranteed. See my feedback. After I clean your site, you can leave the job open for a week.
PS: Since you're new to Freelancer, I will ask that you release the $5 milestone at project acceptance. This will ensure your account is fully setup and can release the bulk of the funds at project completion.