New AdMan Needs Advice on Purchase

[dave_gibbon]

Hi There,
I recently ended up doing some writing and demo-ing for an ad agency pitches. I have now been asked to do a piece for an actual ad. They have agreed on something like $2500 Aus for my budget. I'm running an iBook 800 with mBox1. I've been using a crappy old Sound Canvas that I bought second hand for all my sounds. I've decided this is where I should spend my money. I'm looking for a sound module that gives me a wide variety of usable sounds. I'm realistic about the quality - I know I'm not going to get usable horns and strings from one box. I was looking at a Motif ES rack. Do you think I should get a module or spend my money on a new computer and run soft synths? I don't have much experience with the sound of these though.
Any advice would be appreciated.

Dave