Hi Kundan,
Although the Workload Balancer will soon double its working horizon from 6 to 12 weeks, since that is far short of the three year range you require, I invite you to consider our Resource Contouring solution (with the optional Capacity Charts and Heatmap plugins, as shown in the video). It is configured to start with a year of data, but can be easily extended (under Options) to a three year horizon.
Regards,
Doug