I'm currently on my OPT 12-Month period which will expire the 14th of January.So my driver license gonna expire by that time.but we have 60 days grace period.so wat is the process of getting a DL for that grace period?

I went through similar situation last year. I went to DMV to ask if I can get any authorization to drive while on grace period but they said "No". They need either valid valid OPT card (at least 90 days) or I-20 from School. And I think school does not update Sevis until you attended first week of class. I had to wait till second week of my class to apply for my DL.