At the OP's budget, it's pretty much whatever you can afford. No, you can't get a decent machine because your requirements are too high. But you could just live with a slight wait in rendering, right? Go make a coffee.
Samsung NP530U4C-S02CA Intel Core i5 3317M 6GB 1TB 14in GT620M DVDRW WLAN Win7 HP Ultrabook
$799.99+tax. Core i5, 6GB of ram, 1TB hard drive, GT620M. It's an average machine that runs your software at an average speed.