Why do you need the 200amp service, has the main breaker been tripping? You can't just go and replace the breaker, the cable outside may not be up to size. You
don't need a breaker outside at the meter. If the service cable is 4 ott aluminum, it's rated for 200amp. When your electrical supplier said 220, they were probably
referring to voltage not amperage. It makes no difference to to utility company if you have a 150 or 200a service, and as long as the wires feeding your service aren't in bad shape they will leave them as is. If you want to upgrade the service, you will most likely need to replace the whole service. If it's overhead this means you replace everything from the point of connection (where the overhead wires join with the wires that go into the top of the meter) down to and including the panel. To do anything else with 30 year oldequipment is foolish, it's approaching the end of its life anyway so a band aid or doing half the job just means you are leaving more for later. That way will also cost more. If you are not having problems now I'd leave it, maybe have an electrician take a look and tighten all the connections. If it's in a dry area you could be all set, a very humid basement could be an all together different story.
How many sq ft?
Gas or electric dryer, range, hot H20, ect?
A.C.?
Hot tub?
If you don't have a combination of heavy loads, 150 amps will go a long way.