Upgrading the electric service is an involved procedure that will include one or all of the following: replacement of the service entrance cable; upgrade and possible replacement of the main disconnect panel; installation of an additional branch circuit over current devices (commonly known as fuses and circuit breakers); and rewiring the branch circuit connections at the main disconnect panel. This is a question that you could ask an inspector and receive advice that may help you determine a reasonable plan of action. Anytime repairs are performed on or within the electrical system and its components, a licensed electrician should be contacted to make these repairs.