Hi,
For the gain, perform ac simulation, with a voltage value of "1 V" in your input source (if you design is differential, put +0.5 V on one side and -0.5 V on the other side).
Then, when simulation is finished, open the calculator and enter the ac voltage of output, you can add 20log if you want this : you have the gain.
To obtain the noise, with the calculator, typing VN2() will plot the noise power density. You can take the square root and integrate, depending upon what you want. You can also ask, from ade window, print-> noise summary.
Regards.