chollie: Thanks for the interval training suggestions. I did 10 minute run/5 minute walk intervals today (though the last was a 5 minute run), bumping up the speed at each run interval, totally 35 minutes running and 20 minutes walking. It definitely helped, and I probably could have done another interval or two if I'd had the time.

MoreMilesPlease: My building has a small gym, but not a ton of amenities. A couple treadmills, an elliptical trainer, a bike, a lousy combo weight machine (similar to this), a couple benches & a bunch of free weights.