Sounds like you hired the wrong kind of agency. You don't want a "new media" or ad agency. These guys are used at gobbling up the huge corporate budgets to create big splash marketing that doesn't make sense for any company with less than 8-figure revenue. They do amazing work, but it is utterly pointless before you have the business model locked in to the point that you can scale.

But this is not what all agencies do. If you lack a technical co-founder then you want a technical agency. A ThoughtWorks or Hashrocket or Go Free Range is going to be much better at understanding the nature of a tech startup and they will be able to help you iterate in a reasonable with much better talent than you will ever find by yourself.