M.D.
Hi there!
There are some moms groups in Costa Mesa that meet at local parks and other cordinated events regularly, that would be a great way for you and your baby to socialize.
OC Parenting Magazine and some of the other free local magazines always have ads in them for these groups.
Mariners Church and Rock Harbor Christian also have MOPS, which are groups of moms that get together to discuss different topics while their kids are in childcare that is provided.
Hope this helps.