Your 2 Gb is not just an SD card, it is a SDHC card. The first 2Gb SD cards, still were SD, but 2Gb was the limit for the FAT 16 and 32 format and for the normal SD cards. The same happened with the hard disks. They developed the SDHC card, and made the new hardware downward compatible with the old SD cards. So in a new camera, you can insert SDXC, SDHC, SD and even MMC cards. But the cameras, card readers and phones, who were made for SD, can't use the SDHC or SDXC cards.
SDHC can work with memories up to 32 Gb and from that on, it is SDXC.
There still should be some 2Gb SD cards around, but not sure you still can fine one. The producers of memory cards now only make SDHC cards and up. Perhaps you only can get some 1Gb cards as SD card, but perhaps nobody will ever make these cards anymore.
I mannaged to buy a 4 GB SD card a few years ago, but that was the last I ever saw in the capacity.