22 here with a 5 month old little boy, living in the Belconnen area also. I've been looking for something like this for a while now, as moved here 4 years ago and have struggled to make friends as well. I found mother's groups here populated by an older bunch of Mums so would really love a younger group of ladies to get to know.
Northside is perfect for me. Ginninderra Lake in Belconnen (as Amandaheming68 mentioned) would be ideal, as it's right next to the mall as well as the strip of fast food/restaurants. Plenty of places to go for a coffee. smile
EDIT: Damn, didn't realise this thread was so old. sad