30 users, 4 routers@2MBPS- internet too slow and most of the times nil

hi terrynet,
thanks for the reply. we have 4 separate routers located at different positions to provide strong connections all over the corridor and the building. Each router has separate connection @2MBPS.

increasing router will shift user load to the new ones , while doubling and tripling the speed will increase the bandwidth i guess. So, i am indecisive what to do and which one would be more effective.