Is it a wise decision to change lawyers?

My current lawyer is a public defender. I am nervous about the sentencing day and would like to hire a paid lawyer instead to do a good job. The sentencing day is in almost three weeks. Is this a smart decision to make? What should i do. This is a criminal case and i feel like a paid lawyer might get me probation instead of jail time. I want someone from out of the city to be able to put up a good fight because i was told that a public defender is coworkers with the DA and such, they wont be able to push through with a good fight.