How long does it take to apply for Visa Renewal at the Osaka immigration office?

With all forms, papers and everything done and finished. How long does it take to drop off the forms and apply at the immigration office?

I saw some mention about an hour?

Also how long does it take to renew? Grace period is 2 months and my Visa expire at the beginning of October. So that leaves me three months. (Should have done it earlier, stupid I know but had a death in the family).