Maintenance after divorce is granted

Can someone help me understand if it is possible to ask for the maintenance for the kids (in my case 3 daughters) after the decree of divorce has been granted. My divorce decree was granted last year February and all the terms mentioned in the petition were met. However, sale of property was also done and there was an X amount that was deposited in the kids name by me and my ex husband, and it was clearly stated that this amount will be used only for the kids and will be taken out only when they achieve the age of 18. Post my divorce I have lost some money of my own as I started a school which proved out to be a fraud franchise. The only source of income for me today is the interest amount that is coming from the savings we have done in the kids name, but that is not sufficient for their monthly fees, leave aside their day to day needs. I am staying in a rented accommodation and is getting very difficult for me to make both ends meet. Please advise if it is possible for me to ask for the kids maintainence from their father. Im 41 and its extremely difficult for me to find a job in this market. also it becomes utmost important for me as a mother to be with my kids since they r 3 girls of age 13 and twins of the age of 7. Please help..