I am looking into road bikes... I have been going to cycle classes for a few years and would like to now try outdoor cycling.

I am 5'0 ... I believe I am a size 44cm. I am a college student and i am looking for suggestions and tips...
Brand... Specialized, Trek, Cannondale, or Giant? does it matter if it is women specific.
Components... Ultegra? should I buy the best? I want a bike that is more than an entry level bike because I know I want to get really into it.. i want it to carbon fiber.
I have saved some money and my limit is around $2500.

I was looking at the 2013 Specialized Amira Sport Compact... but now I am not so sure anymore
Please help me out. I really want to start riding and I have been waiting way too long for a bike and don't want to purchase an overpriced bike

Thanks.