Check your equipment carefully.
"My battery charger won't work." OK, you've confirmed that it will not operate at 220v/50cy, for sure. If this is not an expensive battery charger, the cheapest solution may be to buy a 220/50 charger, and when you get over there, swap it in. If this is a one-shot trip, maybe wait till you get there, buy used and sell it again before leaving.
A more elegant solution is to considered installing a new charger which accepts 110/220 and 50/60cy without any fuss. Run some numbers, it may be an elegant solution, depending on how much power you need to pull.
"I've been told I need a new Shore Power adapter, etc. " Yes, a new adapter probably will be needed. Not a najor expense, check here and there to see if perhaps a loaner is available there, or if not, which side sells them for less.
"All I use A/C for is to run the battery Charger and plug in a laptop or lamp."
The battery charger, as above, has few choices. It is POSSIBLE to get an inexpensive 110/220 voltage transformer, connect that between the 220 dock and your 110 charger, and it will work--if the charger doesn't overheat when it runs on 50cy. Plain tungsten light bulbs designed to run 110/60cy may look a little dimmer on "220 converted to 100 but only 50cy" but they WILL WORK.
And the best and simplest solution if for your laptop: Buy a dc-to-dc power adapter for it, sometimes called an "Airport" because they are designed to plug into car and boat and train lighter sockets. This way your laptop is always running on the nominal "12" volts from your batteries, and it is isolated from whatever AC you are running in the boat. Often uses less power that way as well. Companies like Targus, Kensington,I-Go, and your laptop maker all supply them with different options and tips and prices.
If your needs are simple--the solutions can be equally simple.
Toss in a hairdryer and a marguerita machine, and all bets may be off. (G)
Is there an inexpensive and simple way to convert my boat to use both North American and European A/C?