I'm an alum of Zeta Psi Sigma (soon to be Alpha Chi Omega).
The sorority houses at CMU consist of a duplex and a triplex. The main floor has a living room and kitchen, and the two upper floors have eight double rooms. Here's a (not so great) picture:
http://www.housing.cmu.edu/buildings/sororities/
Kappa Alpha Theta's former house is currently occupied by Kappa Phi Lambda (an Asian-Interest sorority). However, I don't believe they'll be retaining it for next year. There are plans to knock down the wall between two of the houses to make a larger 32-person house, but I don't think that construction will happen for at least another year.