A scene like that shouldn't be taxing your system that badly. If you're having trouble with render times it might be a good idea to turn your AA to the lowest setting possible, assuming you're using LW for this image I'd suggest either 'low' or 'enhanced low' assuming you're not already using one of those... that should cut down your render time without having any noticeable impact on image quality
Edit: caught your comment about waiting for your new computer to arrive.. that's probably worth it if the scene is really giving you trouble.