Mmmmmmm. Tricky one that, I don't know of any apartment complexes round here that also have pools. I would also be very wary of booking anything above ground floor with a 1 year old - the stress factor would be too great i.e toddlers and balconies
However, if you can find a rental apartment in the Portomaso complex then you may also have free use of the Hilton Hotel facilities which is right next door. I know there are usually a few available. It's also pretty central whilst being quite quiet at night.

Hope this is of some help

Ciao

Susan