Hi
I've read your job. What kind of anti-virus scanner do you want?
There are some solution for you. For example, php-clamavlib supported by ClamAV is used for scan uploaded files. It is the anti-virus scanning library from ClamAV. And the other method is using phpMussel. The phpMussel is also widely used, in its config file can set scanning file type, specific directories, achieve files etc.
I hope to discuss more details with you, and also discuss budget.
Thanks,
Evgeny.