To answer your question properly, I'll need to know a bit more:
1: Does the $1,100 budget apply only to the CPU, mobo, and GPU(s), or would it be for the whole system, including both OSs?
2: Where are you purchasing? (country and state/province needed, city ideal)
3: What is the intended use of this system?
4: Is there a specific reason you need two graphics cards?
5: Do you wish to overclock?
With that information, I'll be in a much better position to advise you.