http://groups.yahoo.com/group/tampafamilies/
I am M. and work full time as well. I have a 3.5 yr old and a 2 week old and we live in Riverview. This group is primarily a working moms group. Some of the members live in Pinellas so some events are a bit far for us, but there's playdates every Sat and some of them are in Tampa (Zoo, KidCity, Aquarium etc. There's also a bunch of new members out this way as well so maybe we can start planning more events near us. Tell Calley I recommended you.
I know how hard it is to find other working moms. It seems that everyone is a SAHM. Anyhow, this group is great. Everyone is really nice.
Your child is a bit young to particpate but before you know it, they'll be running around and you'll need an outlet for that energy. I find that we must find soemthing to do everyday with a 3 yr old or she's climbing the walls! So I love weekend playdates.