Your current plan may not allow you to turn it into a Roth while you are still employed there, but once you leave, I assume you should have the ability to roll the 401K over into a traditional IRA, then do a Roth conversion if the numbers suggested it?
"Hey, for every ten dollars, that's another hour that I have to be in the work place. That's an hour of my life. And my life is a very finite thing. I have only 'x' number of hours left before I'm dead. So how do I want to use these hours of my life? Do I want to use them just spending it on more crap and more stuff, or do I want to start getting a handle on it and using my life more intelligently?" -- Joe Dominguez (1938 - 1997)