Find a local supplier of a "document management" system, discuss your requirements with them and see what they come with.
Compare their offer with what Microsoft's Sharepoint offers and with open source applications like found by https://www.google.com/?#q=open+source+document+management
Buying such a system in one thing. Implementing it in such a way that it is being used profitably is quite another thing, and needs a sizeable budget for system management and training.
I run a mid sized business with around 100 employees. I would like to know about a software/tool which can help me out to deal with file management hassles.