she looks likes shes getting pretty close shuvee. i'd a say within the week. i wouldnt keep her in a breeding trap all the time, only when ur not around to be able to watch her (like with work, school, or sleeping). otherwise u'll be able to see when she starts dropping fry and move her into the breeding trap right away. once she starts to become anti-social with the other fish and hide at the bottom, it's a pretty good sign that she's ready to drop. she also may stop feeding when the time gets close. keep an eye on her and if she starts to act a little strange, than it's a pretty good sign shes gonna drop and you should be prepared to move her into the breeding trap at the first sign of fry. if you move her into the trap to soon and leave her there for extended periods of time she will become stressed and abort the fry.
if you happen to catch her dropping fry, don't worry. scoop her up and move her into the trap along with the fry she has already dropped. once shes done leave her in for about an hour then move her back into the main tank so she doesn't eat her babies. good luck.