I understand that this is a "do-it-yourself / How To" board, and I am going to tell you HOW TO stay alive. What you are looking for is something called a "Service Change" and should be done by a Qualified Licensed Electrician. Look in the phone book. This process is way to complicated to explain here in a general way, and it is too important that you get it right the first time.
This is not an area where you should be looking to "save a buck". Go with a professional electrical company that has some time in existence, is likely to be around for a while, etc. You want to make sure they pull an electrical permit before they perform the work.
An excellent choice for your new "breaker panel" is "Square D"
I know a lot about electrical issues, and I know that I would never tackle this project myself.