I think the next most obvious step should be to go for Amazon Appstore. They are serious and if your app gets selected for a free app of the day ..I am sure you'll be flying.
Do you have any stats on what a featuring on Amazon Appstore does for an app?
The appstore was launched a few days ago...
Well the featured app of the day is sold for free, which means a lot of people will be downloading it. And when the app is sold for free according to Amazon TOS, the developer gets 20% of the list price. So if the volume of downloads is immense then you should be able to pocket a decent amount of cash from the sale. Will have to wait a while for the stats though.
It costs $99 just to register to sell through Amazon. He'd have to make a lot more sales to be worth it.