Q: Boot Camp - Can Not Log back into Mac OSX

Greetings everyone,

I was attempting to install Windows 8 on my 2012 27" iMac. I created the partition successfully and installed the Windows 8 OS. However, I failed to install the drivers on to a USB drive to transfer so I could I update the drivers. I attempted to log back into Mac OSX (I am running Mavericks), and I cannot log back in. I have tried pressing the "Option Key" and it does not give me the list of partitions. I have checked "My Computer" and I can only see the Windows Drivers, but I do not see any Boot Camp. Is there a way I can retrieve the drivers or at least get back into the Mac partition and get the drivers and install them back?

Essentially, my iMac is running as a Windows PC...I would hate to loose 500GB for only less than 120GB. Any help would be much appreciated.

-Chris