If you're talking about discs with patches, go to SYNTHZONE - click on the Yamaha page -
Scroll down to Yamaha sites and Yamaha patches. There are several websites where you can download banks of patches. Otherwise, I'm not sure I know what a memory card is - are you talking about a data disc? If so, I've had my sy77 for about 9 years and I've never used or seen one, but I've gotten a lot of great sounds from the internet.