Michael,
I had a look at the product you purchased, and that Voltage Converter is undoubtedly a transformer type, although it's a bit hard to tell from the limited description posted online. That would be suitable for charging low-wattage electronic products such as cell phone chargers, etc. It is NOT suitable for "hair blowers" or other large wattage appliances.
If your wife's "hair blower" is ready to quit, you could either consider buying a dual-voltage model from Magellan's or other travel supplier OR pick up a cheap hair dryer when you arrive in Europe. You might find that hauling a hair dryer to Europe is not needed, as many hotels these days supply them either in the rooms, or on request at the front desk.
You didn't say where you're travelling, but if you'll be both in the U.K. and the continent, you'll need two different styles of Plug Adaptors. I'd suggest packing at least two of each type as they're easy to misplace. You can also get those at Magellan's.
I forgot to address the GPS question. I've been using a Garmin Nüvi for many years, and it's always worked well both for driving and also on occasion for pedestrian use in cities (although I tend to use it sparingly for that, as battery life is a bit "limited"). The model I'm using was discontinued, but there are newer models with the same features.
Some models come pre-loaded with both North American and European maps such as the https://buy.garmin.com/en-US/US/on-the-road/automotive/2013-line/nuvi-2577lt/prod122520.html (there may be others - check Amazon or wherever as the prices may be lower). Since that's something you'll be able to use at home also, it's a good long-term purchase. I'm not familiar with Tom Tom or Magellan models, so can't offer any comments on those.
One other point to mention. If you're going to be travelling with cell phones and especially Smart phones, you'll have to be VERY careful with the aspect of data roaming, as the costs can be HUGE. Doing a bit of homework on the topic would be a really good idea.