Where are you seeing Version 6 Update 1? In the Add/Remove Programs window?

Windows XP SP3 is legitimate. You can download and install with no problems.

As a general idea, tashi (Member of Team Spybot) has posted a sticky which told users that a dated (outdated) version of Java could be a vulnerability for Vundo/Virtumonde infections.

Updating will patch vulnerabilities in Java, but it does not make it Immune.