Amazon.com: PlayStation 3 Memory Card Adaptor: Video Games
Extra accessory. If you don't intend to be using your PS2 anymore after that, it may be better to borrow it from someone else or rent it if possible since it'll be a one-time transfer.
It's also possible to download them onto an SD card or USB drive or something and copy it over from there, but it has to be in the PS3's specific emulator save type. Gamefaqs.com has some gamesaves like that. I've used it on a couple of rented PS2 games where I played them for a while, then just wanted to skip to the ending
