Conver IDE to SATA Raid 5

I have a client whose Windows Server 2003 SBS currently has two IDE hard drives. They are not mirrored – one is drive C: 28 GB, the other drive D: 250 GB. I would to convert this into a RAID 5 SATA configuration, but I don’t want to reinstall or reconfigure the server. How is the best way to do this? Is this even feasible? We’ll probably upgrade the server within the next couple of years. (The server is currently AMD 1.19 GHz w/512 MB RAM and a Travan tape backup. It’s used for file, print and Exchange.)

Thanks,
Jon