Entrance to Italy for work purposes falls under the immigration quota which is established on an annual basis. The immigration quota allows for non-EU foreign nationals to enter Italy for work purposes, including subordinate, autonomous and seasonal work. 

Renewal of Residence Permit for Work Purposes

Renewal of a residence permit can be applied for at the local State Police headquarters (Questura) before it expires or at least within 60 days of the expiry date.
For assistance in completing the application for permit renewal you can go to the Immigration Services desk in Prato Comune or alternatively to an organisation that offers this service free of charge.