How long can you survive on bootstrapping?

Hi everyone. I'm looking for some advice from fellow startup founders/alums about taking the leap from releasing your prototype into the wild to scaling your userbase and product. I'm a single founder of a Boston-based mobile app startup – the product is released, we continue to iterate and build further enhancements, our userbase is excited and giving constructive feedback, etc. We've reached the point where we are receiving interest from companies to buy the app or discuss licensing deals, but interest from local angels is basically non-existent at this point. I quote from one VC: "idea is a feature, not a company".

Here's the problem: I'm completely broke. For this startup, I chose the bootstrapping route. I plunged most of my savings and used credit cards to work with an offshore team and received investment from friends and family to make it past the prototype stage. My development team is willing to take an equity stake to improve the product, but server costs are expensive. Our userbase increased 20x when I dropped the app to free 1 week ago. I cannot afford to pump in $30-40 a day to pay for server costs.

The acquisition talks are positive (it would be a very small exit), but I'd really like to work on building out a company here. Is there any option other than an angel round to make it to the next stage? Would licensing the app to other companies be a detriment in future financing rounds, if we ever make it to that point?