Firstly, this is not a very easy to make site. So your budget, is a bit low.
Secondly, what frameworks would you like? How do you want to deploy? What kind of scaling do you need? How many hits do you think you will get? All these questions are important.
I'm a PHP guy, very good at what I do. I've built many Bitcoin-related websites before and also done security penetration testing for some websites that you've probably heard of!
I also accept payment in Bitcoins, that should be a plus? :)