[AMSAT-BB] ISS Launching Method of NanoRacks and CubeSat TLEs

I recently became interested in learning about how the ISS launches the cubesats that arrive on the NanoRacks.

Where do they launch the cubesats from on the ISS?

Also, when a cubesat leaves the ISS, and it likely has no propulsion to prevent orbital decay, how long are the ISS TLEs relevant to the CubeSats position? Days weeks?