In addition to what's already been said, you could also publish it on competing/alternate marketplaces, such as http://slideme.org/, http://andappstore.com/ and http://www.insydemarket.com/ - they're smaller than the android marketplace, potentially giving your app more exposure.
I noticed your app is 9.5mb; it might deter many potential users from trying the application; especially if they're running on android < 2.2 - almost 10mb of data is a considerable chunk of the available ram. I'd recommend storing the media assets on the sd-card instead (download them from within the app).
Lastly, there are forums where you can promote your apps, such as http://androidforums.com/application-announcements/ and http://www.anddev.org/promote-your-android-application-f22/