It sounds like you really put a lot of effort into your game. Unfortunately, I can’t try it out right now, but I hope you have and continue to receive feedback from the public.
I don’t think spontaneously sponsoring your game solely with the mindset of making your investment back is the best mindset to approach expanding your audience, at least right away.
I would suggest you try and create a rhythm with your advertisements, and pick an amount of your monthly revenue, let’s say, 25%, to put back into expanding your audience. Profitable advertising is not impossible, but it is very hard. The biggest profits you make from advertising are returned overtime, growing a larger purchasing audience. That being said, once you have gained some confidence and rhythm in the effectiveness of your advertising, feel free to spend some increased amounts and really get the game out there.
This way, not only can you experiment with different advertising techniques to find ones that best fit your game, but you can make sure that when you do invest larger amounts of money, your doing so with the most effective strategy possible.
On a side note, I recommend Rolimon’s for better insights on advertisements, especially when your spending a hefty penny.
Best of luck with your game!