Jag,
It will be MyEclipse version 5.0.1. We just (yesterday) released our 5.1.0 release, but that is ontop of Eclipse 3.2.1.
The easiest way to upgrade would be to snag the All-In-One installer we offer now for Windows and install that along side your existing MyEclipse install (note: the installer includes Eclipse/JDK and MyEclipse, so you are all ready to go after running it).