There are many areas convenient to CMU and yes Squirrel Hill is a good one. Unfortunately rentals are at a premium as they are in very high demand and even more so at this time of the year as students and others would have already signed leases for the upcoming semester at the area universities. However there is usually something available although it may or may not have everything you seek.
Have you considered buying a home? You may even find it more affordable and a better investment then renting. If you are interested in discussing this opportunity please contact me via my bio on Trulia for further discussion.
Thank you and welcome to Pittsburgh,