There are many resources to find mobile developers now. You will have to balance your investment level with reliability and quality. sites like Odesk, eLance, Freelancer and others are great resources to post a project and await many bids from developers all over the world...it will be very difficult to really gauge the quality of work...especially if you are not technical enough to review their work. Ensure you indicate very clear requirements and samples. There are often general differences between country of origin. I strongly recommend you work with a fixed bid and not hourly.

Ultimately, it is best to find someone local through Meetup.com events, local colleges/universities and referrals from others.

Sometimes, you can get parts of what you need done through low cost resources.

Good Luck!