New owner with inherited tenants

[Andrew Bravo]

Hello fellow BiggerPocket members.

I have recently purchased my first quadraplex. I have inherited the tenants and 3 out of the 4 units are on month-to-month leases. One tenant in particular is giving me a hard time. The unit she is staying in has been updated within the last 2 years and her previous rent is below market value rent. I have presented a new lease to the tenant with a fair market value rent, but she refuses to sign it. I am willing to be flexible with her first month rent due purchasing the property mid month. After that month If she still refuses to sign the 12 month lease, what should my next steps be?  How many days am I legally obligated to give her to move out in the state of Georgia if she refuses to sign the new lease?