It will speed it up quite a bit if you don't use the best possible settings for GI, for example. Maybe your client won't notice the difference if you lower settings on all the rendering parameters. They're right about graphics cards - those things only speed up screen displays, previews etc. They don't do the final render calculations. If all else fails, switch to a dual 2 or 2.6 GHZ G5 with 2 or more GB RAM.