I think you're vastly over estimating the impact of tech news sites. A decent front page article on techcrunch will get you a couple of thousand visitors, the vast majority of which won't be in your core customer group.

The main advantage of tech news sites is that they're read by potential investors, partners, employees, etc. rather than because they get you users.

You really need to get your early users through graft, tech news coverage won't really help you except in exceptional circumstances.