2013 27" iMac GTX 780m driver issues

Im a music producer by trade and my DAW of choice is Logic so of course i use Macs, im also a casual gamer but cant afford two machines and also i dont have the space, so when i saw that Apple has updated their iMac range a few weeks ago and that the top of range iMac was going to feature a GTX 780m i was extremely excited, I had an older 2011 21.5" imac and the graphics card wasnt really up to much in the way of gaming but still runs perfectly for Logic etc etc so this seemed like it would ansswer my prayers and i would at last have a suitable machine to fit both my wants and needs, a workhorse for my job and a pretty decent gaming machine once windows is installed via boot camp.

BUT after spending near on £3000 the iMac came and once i installed windows i was excited to check out how well it could game, however, bootcamp installed very very very old Geforce drivers and most new games require newer versions of drivers to play better, in fact the battlefield 4 beta demands that i update the drivers for my GPU

This is where my issues begin, when i run the automatic driver updater it claims that my drivers are up to date when they arent at all BUT when i manually find the correct driver (that isnt in BETA form) the install starts and it states that it cant find the correct hardware (implying that the driver it wrong for the GPU) i am 100% trying to install the correct driver i am aware that the 780m is different from the 780 it is a laptop/mobile GPU i am 100% selecting the correct one, the only driver that installs is the newest BETA driver BUT that gives my an issue that when i turn on my iMac and hold the alt/option key to select my windows partition it loads up until the windows 7 screen (with the windows logo) then the screen flickers and goes to black and it doesnt boot... ever... no matter how many times i restart and retry, in the end i have to boot in safe mode and uninstall the drivers.

i understand that BETA drivers WILL have issues but why wont the correct drivers that ARENT beta detect the correct hardware? im stuck now, i have effectly wasted £3000 in a machine that i didnt really need as my old iMac was fine for my job, it ran perfectly, i just wanted the gaming experience that seemed so possible with the updated GPU.

Does anyone know of a work around? or a solution?