installing bootcamp help

hello,

i know there must be thousands of current threads on this but I'm looking to run bootcamp so i can run some rendering software, obtaining and iso image is as far as I've got and I'm wondering how to obtain one? and id read that bootcamp also requires the window operating system and was wondering if there was any particular windows software to buy? as i thought about going out to buy an install disk however didn't want to spend x amount of money on it if it wouldn't work.

thank you,

jake