RAID to replace SCSI drives on 2k srvr

Currently have a Dell Poweredge 1300/200 sql server with two 9 gb Seagate SCSI drives that are running out of space. One of them is just a mirrored drive. There is not an extra bay in the PC to fit another drive. I already bought two 18 gb Seagate SCSI drives to replace the others. I can’t afford to buy Ghost Edition 7.5. and I have heard that regular Ghost Edition may not copy all settings on 2000 server. There is already RAID card (0), but I need a quick education on RAID and any other advice. Thanks!