1. Is the price right? Well it's not wrong on the '13 and suspect the dealer paid too much for the '12 if you think he won't budge.
2. I don't believe it's a huge advantage but you're probably better off just going with the '13.
3. Seems like you're fixated in the color and if so then just bite the bullet and get the '12 if you're ok with the price.
In the end if you're looking at dumping the car in the near future, well all I can say is that unlike the Elise/Exige, these cars don't sell as fast so be prepared to either playing the price games or to sit on it for a while. Otherwise just enjoy the car and drive the crap out of it...will make your life less stressful
The auto base cars are exactly the same as MY11's and it's only when you choose one of the premium pack options where you start to see the difference in interior. That said, the steering wheel is different, the sound of the door when you shut it is better, the exhaust is improved and the overall fit and finish is better as well. I've had base model MY13's & '14's next to MY11's and can see and hear the difference.
Hope this helps the OP