I don't think there's a way to re-download the software without help from iFly cusomer service. iFly Connect only downloads the data files.
To use the iFly GPS software, there is nothing unique about the SD Card. You can, in fact, just copy the files from one SD Card to another and it will work.
The iFly Streets navigation app used to have some copy protection that was tied to a physical SD card, so you couldn't duplicate it. I have never used that software, and don't hear much about it anymore, so I don't know if it even still exists.
Call customer service during business hours and they'll get you set back up: 214-585-0444