Sorry to hear about your iMac
You should be able to get some cash back for your current iMac as spare parts on ebay towards your new machine.
Keep an eye out for Apple refurbished iMac's - they are like brand new and much cheaper (from memory the 21" iMac was something like $999) - they pop up daily - free delivery too.
Dick Smith also usually have a 10% discount on Apple from time to time.