There are not too many chargers out there that charge multiple batteries. I've seen a couple on the Hobby King site that can charge 2 but they are not overly cheap. This is probably why a lot of people simply buy 2 or 3 cheaper chargers and then just run them off the car battery at the field. It's not uncommon to walk past the car park and seen several hoods up with a couple of chargers hanging of the car batteries.

You do want to buy a dedicated LiPo Balance charger (though they will also do most other battery types).

I use a Turnigy Accucel-6 80w unit which I purchased a few years back when my old original Swallow charger became unreliable. The Accucel-6 is a very nice unit and not too expensive. It (like a lot of others) runs of 12 volts, so ideal for taking to the field. At home I have a 12 volt power supply plugged into the mains to run it. There are also Mains and Mains/12 volt options.

So you may want to ditch that supplied charger and look to a decent LiPo balance charger, especially if you intend to stay in the game for a while. It will be worth it in the longer run. But get a Balance charger. Most hobby shops have lots of options with different power outputs and higher cell counts.