Time is money. Really your not saving your company but costing them money in lost productivity. The time you spend waiting for an animation to render is time you could have spent on rendering another project.
Take a look at this farm, I don't have personal experience but I hear good things.
http://www.rebusfarm.com/
Remember to forward the cost of rendering to your client, you should not have to eat that expense.
FYI a i7920 rig is around £1.2-1.4K, you can get a dual xeon rig for £2.1-2.2K