As someone who got started with Windows Movie Maker, I speak from experience. You're going to want to upgrade.
It works well enough for the video portion, even captions and adding music wasn't so bad. It's adding all the extras where it falls short. I'm not 100% on this, but I'm pretty sure you can't adjust the orientation of the video layers in Movie Maker.
If you can "acquire" Adobe Premiere Pro, it was a great transition for me from Movie Maker. Easy to use from the get-go, with lots of room to grow as you become more familiar with the interface and it's capabilities. 9 times out of 10, if I couldn't figure something out, I could just Google it and find written directions, YouTube tutorials, troubleshooting forums, etc. that solved my problems. In the past couple weeks I've taken the leap and learned how to make my own strokemeter with Adobe After Effects (many thanks to
brewster's video guides on YouTube, see this thread for links:
http://www.milovana.com/forum/viewtopic.php?f=25&t=8721) and it's been very easy to integrate into Premiere Pro, putting it wherever I want it to go, adding transitions, etc.
My advice would be to finish your video with Movie Maker. It's what you're currently familiar with, and will ensure uniformity for the full video. Once you're happy with it in it's current state, export it to video and then, if you choose to use Adobe Premiere Pro, you can very easily drop your finished video into Adobe to continue the extra editing. This would make it very easy to add the stroke meter.
If you want to take the plunge and have any questions regarding how to start out with Adobe Premiere Pro, I'd be happy to help!