The problem with your question is that the answer is highly ambiguous. Asking how long it will take to implement those features is a bit off; instead, you should be asking "What needs to happen to implement these features and what would you estimate all of it to be?"
Just a search feature and social networking/profile feature implies a whole gamut of underlying logic that you aren't aware of (because you aren't a developer). Depending on what your vision is, those two features alone could end up being a two month long project just for a first iteration (don't forget about iterations!)
I charge about $65 per hour for web application programming work in either Python or PHP (I prefer Python), I segment my time into 40 hour work weeks. For two months of work that would equal out to a little over twenty grand for a first iteration. That does not include going through QA, user acceptance, feature list refinement, and finally a second iteration (then a third and a fourth and so on for as long as your product stays alive).
Many non-technical people trying to get into the web startup or software startup scene see that price tag and commitment to time (through iterations) and have a mini-gestalt. They simply aren't aware of what goes into building a reliable, feature-rich, maintainable, and clean web application! This is why almost all of the successful web startups have been built by people that do the work for a living already (or some by very wealthy people that can afford it), because they don't have to go pay a lot of money for someone else to do it, they just have to pay for their living expenses.