Mommy Groups in the area

I live in Regent Square and my son was born one month ago as of tomorrow! I am new to Pittsburgh and thought I would meet other mothers during the pregnancy/birth, but I haven't. Now that it is getting cold and I will be returning to work soon, I have realized I need an outlet. I tried to sign up for a mommy group but saw most of the dates are while I will be at work, and that I will be rather consumed with my little one and less inclined to drive outside of my area. One group had a handful of weekend events but everything had an admission price and that was also a concern as I will soon be paying for childcare.  

I just posted an ad on Craigslist activity partners to see if there are other mothers in my area, but I'm a little nervous about going that route. 

If anyone knows of a group already in the Regent Square-ish area or any suggestions on getting to know other mothers, that would be great.