Krusty, current requirements as Dreamjob wrote. Obviously it depends on how many "upgradeable" FO's you have ahead of you in seniority.
My answer is "less than 2 years".
I would be completing ATPL's as a matter of haste. Your day-to-day workload will be fairly high with not much time to study, unless you use annual leave to do the work.
Good luck to your family.