$5000 budget for Social networking site second phase development

This is a top project, it is a social networking site we have been developing since early 2010, although we temporarily paused development at the end of 1st quarter of 2012. We wish to resume development with immediate effect and assume this next phase of the project must be completed on or before end of March 2013 or as agreed. The site was developed from scratch with passion, and we have worked with some inhouse top software programmers and developers in the industry. So, needless to say we are only inviting bids from the top industrial people, agency and individual at this time. Your business must have been registered for at least 2 years in whatever country you are based and a minimum 4yrs experience is required of you or anyone of your team accessing our code. This project has evolved and metamorphosised through ideas and contributions of our staff and people involved and we want our work to be respected so an NDA will be signed before gaining access to our site or code. Previous experience with algorithm, social networking and facebook like user feed very essential. This is not an hourly project, it is based on limited budget and we have a budget of no more than $5000 for this next stage of development, we may be able to scale a bit but ideally we would want to remain within the comfort of this budget. $2000 going straight into escrow the moment this project is awarded. A further $1000 will be escrowed on or before 15th of January 2013 and balance of $2000 goes into escrow by end of March 2013. We would also give you much consideration if you are within freelancer/scriptlance top 20 ( Note that this is not a compulsory prerequisite for bidding) We like to work with real and friendly people, not a team that will route us through a customer attendant, or dedicated skype person. We would not deal with a third party or an intermediary who will ask "what project are you talking about". We understand this is the case with most agencies but we want to deal directly with the most person in charge of our project if it is ever awarded to you. If we don't respond to your bid within 3 days, that means your proposal does not meet the standard we are looking for. Only short-listed contractor will get access to our website, so don't ask until you have been short-listed. Project will be awarded by end of Nov 2012 or before the 2nd week of December. Happy bidding