Ask HN: Need advice on marketing and distribution

I need your help regarding marketing and distribution of my web app - DomCop.com. I am a techie at heart and find myself a little lost when it comes to sales, marketing and distribution. I hope someone can help guide me.

I launched DomCop.com a few months back and I've had lots of great reviews from (paying) customers on the app functionality, but I am having a terrible time reaching out to new customers. I have tried the following channels for distribution.

1. Posting to forums in the seo/domain auction niche - I got most of my customers from here. However, I do not want to spam the forums and therefore this channel becomes very limited.

2. Running banner and text ads on forums - this has surprisingly not been effective on the very forums that customers have converted from regular posts.

3. Google adwords - these are proving to be too costly and are not as effective as forums.

4. Facebook ads - these ads were cheap - but have not been converting.

5. Stumble upon - same as facebook - cheap, but not converting.

I've read on HN that blogging in your niche and contacting other bloggers is a great way of getting good traffic. But, I feel like that would take away the time I could use to add more features (especially ones that current customers have requested for). I am trying to work on SEO as well - but this would take a while before it generates decent amount of organic traffic

Are there any other channels that I am missing out on? How do I go about this? Should I try and get someone on board who has knowledge of internet marketing and sales (a business co-founder). I am a programmer by profession - so not very sure if I have been going about this the right way.

Thank you for your time.

Akash

A little about DomCop.com - The app provides information on expired domain auctions - verified page rank, SEOmoz and SEMrush data, social stats.