Irish Driving license from the US (Cork)

I understand that I can legally drive for 12 months after I'm in the country, but what I can't seem to find info on is, can I buy a vehicle and register it without having an actual irish license. I know i'll have to take 12 lessons at 50 euro a pop, but can I do this while my permission to drive is still good?
The thing is, I NEED to be mobile the moment I get there, as my business depends on it.