From your question, I'd guess you don't have enough money to pay for the application to be developed. Software, particularly good software, is generally a lot more expensive than somebody outside the field would expect. (This is also a common point of friction; non-programmers frequently think programmers are padding their schedules to get more money or an easier job, and programmers frequently are frustrated by non-programmers not understanding all that has to be done.) There are places where you can hire programmers cheap, but they won't be able to afford to do good work.
There's also the question of your idea. Since you aren't a programmer, you likely don't know what would go into it or even if it's feasible, and the only way you're going to find out is to share it and risk somebody else using it. Ideas are usually worth a lot less than the person with the idea thinks (although there are exceptions, the spreadsheet being a star example), and you won't get much out of just having an idea without helping a lot with the execution.
You really do need some sort of programmer partner to help you evaluate the idea, and unfortunately you have no good way of telling a good one from a bad one. (Programmers have trouble with this themselves. Look at the data on variations in individual productivity, and all the blog posts about how to hire good programmers.) You also need one you can personally trust, and this probably matters even more than quality.
So, you're not in a good position here, I'm sorry to say. Try to make personal contact with a programmer you think you can trust, and explain the situation. Don't expect to make lots of money from having an idea without putting in a lot of work to make something of it. Prepare to be generous with equity shares: most likely, your idea will fail (which is what startups tend to do), and it might really take off (in which case the equity you retain is likely to make you rich anyway). The odds are very low that you'll be thinking "Darn, if I'd kept that extra 20% of the company I could retire now."
Good luck. You've got a hard job ahead of you.