For a quick conversion like that, I'd recommend using an instant exchange service. Paybis is a good option for this specific need. You just enter the amount of BTC you want to sell, and they show you the exact USD amount you'll receive and the processing time upfront. The transaction itself is usually very fast. You can go directly to their conversion page to convert btc to usd and see the live rate. I've found the whole process from sale to bank transfer is often completed within a day.