I say go for a windows type computer as macs are designed for more graphics and art.
You can pick up a basic acer aspire for around 749 come with vista i think you can get it a BigW or Kmart i forget which one had it but you get 100 dollar cash back from the company so bonus. Or you could look always on ebay they have some really good one and cheap too.
SW: 126 kgs
CW: 122.8 kgs
GW: 60 kgs
Mini Goal: 110 kgs