I have been told that whareabout enginearing has a plasma cutter but cant verify that personally. http://www.yellowpages.com.au/onlineSolution_moreInfo.do?z=100007&iblName=We%27reabout+Engineering&iblId=2971882&authToken=105f7bfb65e%7C72c77901b0184b6da376a04c9ce16a3c&st=bn
The sheet metal company I worked for got all their laser cutting done by these guys:
National Laser Group ph: (03) 9580 1066 Laser Services &/or Consultants
If you just want a plain grill (square or round holes) it may be cheaper to get it done on a cnc turret punch as it would probably be cheaper, but if you want a pattern cut out then you'd have to go laser.