Backups

I have just started doing a "data and system state"
backup to an extra hard disk on my computer. I have
named the first backup as a code number for the
day/date/year of the back up and have the schedule set to
overwrite each day at the same time. Is there a way to
(A) have the date code change automatically and (B)
should I have a second back up to overwrite and have the
backup schedule overwrite the oldest each time.

I am running WinXP Pro with 2-160G hard drives using only
XP's back up utility (no RAID or third party software).

Thanks