Suggestion on some subversion tool for managing software

Hi,

Our asp.net application is enhancing day by day and more than 5 staff is working on the project, it is messing up to maintain the version and tracking who is working on which module who spend how many hours on each module etc etc.

Please suggest some tool where by we can maintain the change version of application, assign task to staff, who spend how many hours on each module and simultaneously staff can work on the project.

Thank You