M.N.
All the small communities in this area have a little throw-away local newspaper... If you are use the RSM gate, Pavillions, across Antonio, carries this paper. You could put a little ad in the paper ... "New Mom with (kid ages) looking for mom's and kids to exchange play dates."
Secondly, go online and check out the Mom's Clubs in the area...
My daughter moved to Coto (in the Village) two years ago with kids aged 8, 10, 12... Scooters and bikes are a good way for the kids to peruse the neighborhood on their own (or with you watching/walking). The village has the old tennis club with a small resturant and a great pool... Nearby is a riding stable and the old store which I think may be open... Might meet mom's there if you play tennis??? Eric or Katrina can help you.
Finally, now that the teachers are back to work... my daughter found volunteering for classroom duties helped her keep her eye on each child's classroom (and kids the same age). There is a sports center at Antonio and Empressa that offers various after school classes for the younger set.
My daughter found the families are pretty friendly in Coto... I'm sure you will soon have so many ways to go you won't know what to do first!!!