You don't say why you can't upgrade which makes it hard to help you.
However, a 2GB can be used, but it has to be set up right. There are two "formats" (ways the card can be set up) that might be used. One is called FAT, and is OK. The other is FAT32, which Eclipse can't use at this time.
You must make sure that your card is setup as FAT. On Windows, this is an option on formatting the card.
You should tryand find a local computer person to help you. Otherwise you can order a card from Eventide.