Hi:
I'm wondering why you aren't starting a business to produce this app yourself?
Develop a prototype, show it to likely users, take their feedback to refine the product, build a marketing plan, launch the product and generate sales. Once you've proven that it sells and customers value it, this company could look at the decision to acquire it as a no-brainer.
Also, in terms of what to expect, this company you have your eye on would likely be looking to pay the fair value of your company, which probably has no correlation to their market value.
If you wish to discuss, send me a PM through Clarity for 15 free minutes.
Cheers,
Kerby