You are in a good position to have revenue. That makes a lot of things easier, including raising money should you need it.
Your real question right now is how can you increase your sales. I have no idea what your app does, so I can't say what your industry standard should be, but if you are able to get $150K in six months, you should be able to double that within a year. And you should think seriously about that because within two years the market will have changed so much your app might be of much lesser value to users. The key is to maximize revenue now as quickly as possible.
So what will it take? What do you need to spend money on to raise your revenues? Again, I have no idea whether you need to increase your ad budget, bring on a well networked person as part of your management team, or whatever. That you need to figure out. If you cannot pay for that out of your revenues, then you need to raise funds from angel investors.
How much? Again, I don't know, but you shouldn't be looking for millions at this point. Based on what I have seen with previous companies in your situation, I would guess that somewhere around $1M should be enough to increase sales by 3X to 5X. That would raise your company's valuation to probably between $8M to $10M, and so after about two years, you sell the company. That would be an attractive return for most angel investors.
Bottomline: You have to think strategically -- how little money do you need to achieve the greatest bump up in revenue. Then how will that affect the valuation of the company and put it in a position to sell fairly soon at an ROI that will be high enough and soon enough to attract angel investors.
