G'day fellas..Happy New Year

On my 02 VX SS the battery light is starting to come on. First it was a flicker at high revs now it's coming on more often and staying on longer.
So.. I think I need a new alternator.

Question is: Which one? What models use the one I need? as in VT-VY?

They've got them at Holmart for $289..
http://holmart.com.au/online/prod576.htm



And eBay has then for $239
http://www.ebay.com.au/itm/New-Alter...2d54045&_uhb=1

I used the compatibility chart on that eBay one and it said it's not compatible with my vehicle. That can't be right? So that got me thinking about compatibility issues and confused as to which one I need for my car.

Can anyone help me out here.. I'm a bit confused now.