Pick up an Orion 1600mah 5 cell hum pack, I have two that have lasted forever. Dynamite makes good affordable chargers that can charge 1-8 cells at different amps. E-Bay has some good deals on Dynamite chargers for around 40 bucks.
Pick one that can charge 5-7 cells at a minimum. The Prohet series are easy to use and reliable.
I've got a little older Dynamite Mega Peak charger that I used just for what you're going to do. I charged my 1400 rx pack and 2000 roto start pack with it. I'm selling it since I do a lot more charging now. $15 shipped if you're in the Con - US