You can calculate the base amount of your bill by going to the "Shop" link at the top of this page, then "Plans" and adding up the cost of your new calling plan and any other features, like texting packages, data, VZ Navigator, etc. That will get you quite close to the total of your monthly bill.
As far as surcharges and taxes, you'll have to wait until the bill comes to see them exactly, but you can estimate them by looking at your previous bills. Your surcharges and taxes will represent roughly the same percentage of the total bill before and after the change.
Finally, remember that your first bill will be higher than normal because you have to pay one month in advance for the new plan/features. Your second bill will reflect your monthly cost (+/- a few cents for varying taxes) each month.