I would like to hire a Bitcoin Expert ( I need an exchange, multi currency)

Would like to open a site, I already have over 50 clients who will use service. I need to understand how the transactions work behind the scenes, from the time the order is placed by the client to the time we receive cash and they have their coin/ currency. ( PLEASE INCLUDE THIS IN YOUR APPLICATION OR DON'T BOTHER, ( SORRY TO SOUND RUDE) ) We are after a dev for the whole project, so dont feel shy to tell us what else you can do! ( THIS IS LISTED AS A SMALL PROJECT, I DO WANT THE BEST PRICE POSSIBLE, BUT WILL PAY FOR QUALITY , CREDENTIALS AND QUICK ROLLOUT) So if you (REALLY) stand out, ignore the price , I'll pay more.