Congrats!!! Oh I bet she was just seeething when she left. Now that you have a CO amount....do NOT pay 1 penny more! If the kids need clothing and you buy it...KEEP IT AT YOUR HOUSE.
Do most certainly file for the divorce and put together a reasonable
parenting plan....then put together another one that is padded with things that you're willing to let go of. In other words...start off asking for way more than what you would settle for.
Around here the saying goes "pick your battles carefully"....it appears your
BM didn't...too bad for her!
Important things to have in your parenting plan....Right to first refusal. Meaning that if BM isn't able to be with the children during her parenting time, then the children should be with you unless you are also unable to be with them. Say BM has to go on a work trip for 3 days during the time the kids were supposed to be in her care. The RTFR clause will insure that the kids stay with you vs a BM family member.....MOST of the time...sigh. Remember this parenting plan has to cover every aspect from now until they are 18 or depending on what the age of Majority is in your state.
Good Luck!