How do I get reimbursement for travel cost now that my ex doesn't have a car and I am the only one transporting kids to and from his apartment?

If you have a stalking injuction, I'd need to see that and determine what it says about having the children around. And, if he is having these mental breaks, should the children be around him at all? At least not until he is stable and able to safely care for the children. With those things in mind, why are you taking the children to him? I think you need to review the entire situation with an experienced family law attorney to determine what your rights are, what his rights are, and what changes need to be made to provide safe environments for the children, and help you out with your finances. I may be able to assist you, should you want.   David R. Hartwig