Wait a few days. If you've written a good project description (and if you're a bit lucky), you'll start to see a few qualified proposals trickle in.
This is the main problem with freelancing sites. The race to the bottom finished years ago, and the result is that there are simply no good developers or designers left there. It's actually an opportunity waiting for talented newcomers, since a single person showing up and acting professionally would get the job described by this poster (and everybody else who goes there seriously looking to build something).
I took the time to write up my experiences with these freelance sites a few years back:
http://www.expatsoftware.com/articles/2007/09/how-to-fail-at...