There's really only one place, more or less, that's: www.hobbyking.com
. Anyways, order the 'Turnigy-Nanotech' line of lipos, just get the appropriates size, voltage and milliamperes you're supposed to have. Each product has a 'US Warehouse' listing/option, use that, unless you want your orders to take awhile. They also sell the IMAX B6 balance charger which is great bang for your buck.