Do I have to increase the water line diameter all the way to the water meter?
I'll disagree a little - LESS 1/2" pipe has less restriction than MORE 1/2" pipe. Now, in most cases the pipe outside your house is far more than the pipe inside your house but depending where the meter is, if it's a short run from where you increase it to the meter (one of those deals where it's sitting on the outside wall of the house, say, and is fed by a larger line)  and it was formerly the case that the entire water service in the house was a single 1/2" pipe, you might well see a noticeable improvement (though it is of course better to have a larger pipe all the way back to the meter.)

Now, if there's 100 feet of 1/2" pipe from the house to the meter, or from the water main to the meter, you're not going to see much improvement if you change 20-30 feet inside the house.  But if it's 3 feet to the meter and 30 feet inside the house, you will notice an improvement.

And, if you want to get sneaky, you can have a huge improvement (for a set number of gallons) by installing a pressure tank (as for a well pump) in the house (along with larger pipe, or a PEX manifold and a lot of home runs), so the 1/2" line is not required to supply water as fast as you use it, until you draw down the pressure tank. Not much help in filling the tub, lots of help in refilling the toilet when it flushes without dropping pressure to the shower precipitously. How many gallons would depend on how big of a pressure tank you buy, and how much your pressure varies with use (now.) Just to toss one out there, especially for the folks with a charge by size of line into house. More extreme setups might throw in a booster pump, too; I'm not going to suggest that without more data suggesting it would be worthwhile...