Need help to get three year PGWP

[Shivin]

Hi guys I need your help to take my decision.. I came in canada in may 2015 I have completed one Semester in public in sep 2015 then I have completed two year post secondary diploma from private designated learning institution.. after that I did not apply for PGWP..Now I am doing one year post graduate diploma from public college. I will graduate in December 2017 .. if I will apply my PGWP in dec. What will be the length of PGWP. if I want to get three year PGWP. What should I do. My new study permit will expire in 31 march 2018.. I will graduate in postgraduate program in dec 2017. If I will take one more diploma of one year. When should I start that diploma in Jan 2018 or may 2018..if I will start my new diploma in may 2018 they will consider my continuous study or gap in my study .. please I need expert advice for my case ... so please guys give your sujjestion.. if you will help me in this case the god will help you.. thanks you so much..