Rikki:
Here are a couple of Australia links that will get you started. The new small Apple unit would permit BOTH Windows and Apple software to be used (this is a brand-new situation). http://www.apple.com/au/macmini/
(Apple gear is expensive but sexy)

Dell is one of the most popular "build to suit customer" operations in the U. S. http://www1.ap.dell.com/content/products/category.aspx/desktops_au?c=au&l=en&s=dhs
(Dell PC gear is competitively priced)

I build and program my own computers (PC) but this takes a few (LOL) years of practice to get it done and keep your sanity. Let me know if I can provide more useful information. I want to know more about OMB from you (soon I will ask the questions).