The main reason for doing a RAID is reliability, if one or two disks fail you information is still secure. A two drive RAID makes no sense, you can't do striping or have a spare hard disk and any RAID features would involve a decrease in what is a tiny amount of storage space to begin with.
Now if you had say 7 or so 300 GB you could construct a relatively reliable 1.5 TB RAID. But you don't. Also it appears you are the only user. RAIDs are most useful in systems that get a lot of access from a lot of users.
