If you are planning to move and get a Dual Xeon E5 processor it will be a very good improvement because you will not have only one processor working, you will have two units working at the same time. I don’t know exactly which the model is, but the features of this type of processors comparing with the E3 are better. For the type of work the system is dedicated the video card and the RAM have a lot of work too, if you have the chance to add a second video card using an Nvidia* SLI* bridge or ATI® Crossfire* that will be a very good improvement too. Talking about RAM, if you add more memory the time the work takes will improve too.
About Intel® Core™ i7 processors are a good option too, the unlock version for 2011 socket, X79 chipset motherboard are excellent choices, but they are a little expensive.