Some people have had luck getting their hands on a PC PCI ATA card and plugging it in and having it work -- for some reason, it had both the PC and the Mac ROM on it. HOWEVER -- I wouldn't chance it unless you can afford it. Definitely not by ordering one online -- the nightmare of trying to return it and get a refund would make your head spin.
I don't know the Australian to US currency conversion... do you? I don't know how much $399 converts to in US dollars, but the Radeon 7000 PCI should be around $100. The regular Radeon PCI card should be $150-$175. The difference is that the 7000 card doesn't have any hardware acceleration -- like RAVE. The Radeon regular does. But, I can say going from a Rage 128 16MB PCI to the 7000 has done Quake III and Urban Terror WONDERS. I can play now at 1024x768 with ALL options on and it's smooth and looks great. With the 128, I was playing at 640x480 with medium everything -- and the cool lighting effects off.
For your setup, the 7000 card would definitely help with the games. Photoshop would see a slight boost. Not sure about Lightwave -- that might be more hardware-dependent, and I'd assume you'd be better off getting the regular Radeon card -- but please, don't take my word for it. I don't know -- just guessing. What card do you have right now?
As for the ATA card, mine isn't a RAID card so that's why it was so inexpensive. Sonnet also makes an ATA66 RAID card for $150, but I wanted a single hard drive -- not a RAID setup -- so I went with the ATA100 card. What kind of computer is this going into?
Good luck -- lemme know if there's anything else I can elaborate on!