Proof of concept social networking site HELP!

Avg Bid (USD)
Project Budget (USD)
$250 - $750

Project Description:
I am brand new to freelancer and interested in getting some feedback from you as to how I may be able to go about a project which I am just getting started.
Essentially what I need is a social networking site that I can have a three tiered member structure which allows businesses to promote projects to other businesses and individual members. The site needs to have three specific profiles, search functionality, private messaging, forums and other general social networking features.
I have some specific details and breakdown of how I want this all to look but first I am looking for a web developer who can design a Proof of concept (POC) for me so that I can present this as part of my start up funding request to angel investors. Obviously if you can successfully build the POC for me you will be the first person I think of when it comes time to build the fully functioning site.
Please respond back to me at your earliest convenience as I have a very tight time frame which I need to get this project completed in. I have put a cost of $250 against this project as it is simply a POC at this stage but I am happy for you to also quote me along the way for what you believe the full operating site may cost.
Thank you I look forward to your response.

Skills required:
HTML, MySQL, PHP, Social Networking, Website Design
About the employer:
Public Clarification Board
Bids are hidden by the project creator. Log in as the employer to view bids or to bid on this project.
You will not be able to bid on this project if you are not qualified in one of the job categories. To see your qualifications click here.