Screwed up installing Windoze... :( Help!

Well, I just got a new imac 21 inch. It's the latest model running 10.8. Wanted to install Windows 8 so our teenager can play his shootum up games. Bought a Windows 8 install over amazon. Came in DVD format. Doh! no DVD drive on the imac. Solved it by creating an ISO file from the DVD and putting it on an external hard drive.
Ran bootcamp. Everyting going well. i hit a snag point where it gave me a message that the partition I was trying to install to wasn't formatted correctly. It asked if I wanted to format it. I picked the 50 gig bootcamp partition and said go ahead. This worked and windows installed just fine. The machine rebooted and then restarted in windows.

Now I can't get back to OSX no matter what I try. Already tried
Option key on startup.
Resetting pram
Creating a bootable install disk and restarting with the C key.
Shift key on startup.
No matter what I do the computer will simply just startup in Windows.

I'd like to be able to just start from scratch since I haven't used the machine at all but it won't even recognize the install disk I made on a hard drive. At a loss here as to how to proceed?

 

Solved!

What a head scratcher. Turns out it was the bluetooth keyboard. It was connecting too late and not registering my key presses. Plugged in a usb keyboard and everything is fine. Wondering if I'll have to ditch the bluetooth keyboard in order to boot between systems?