In order to upgrade your electrical capacity, an electrician must be contacted absolutely. In most case the wires that makes the connection between your electricity providing company and your breaker box needs to be changed to a greater wire gauge. In most states, the electricity provider must be contacted prior to making any changes to your electrical entrance, and they will accept only a demand made by a licensed electrician. also your breaker box will need to be changed, sometimes they need to change the pipe outside the house in wich the wires run through to accept the size of the new wires. I cannot give you and idea of a price, you will need to get estimates from a couple of companies. there is lots of hardware needed to do such a job and it can take about 3-6 hours to complete the job.