How do i remove a public Guardian and have myself become the Guardian of the estate

I Have a question,, how hard would it be to switch over a (Estate) Guardianship/conservatorship from the public Guardian office of alameda,to myself the minors grandmother/caregiver..my son went to prison and Alameda took over the Estate five years ago.at that time i started taking care of my grandchild i live in fresno. when my son set up the estate with the money that was won from the vaccine injury compensation program.all the money in the estate (250thousand) is to be used for her injoyment and Happyness. her life expectancy is short she has 10 to 12 seizure's a day,her seizure activity is what determines her activity and attention span.she cant walk ,talk or eat anything by mouth,,.i want to ask the judge myself to use funds for a trip not have to use a public Guardian