Not following divorce agreement

My ex spouse agreed to pay for my $165.00 of cell phone bill, car insurance for me and my cobra health insurance for three month from the date of our Final Judgment 01-04-2013 plus three additional months if I have proof that shows I am working full time and furnish him with this proof. He has also agreed to pay for my son's car insurance and cell phone until he reaches 21 years of age.

In turn I am to hand over a few personal items he wanted which I have done, I had to have tax information sent to our CPA without a deadline date and I have to change the title of my 1995 Nissan, which is solely in name, to my son, it doesn't state a deadline date but the last part of the decrees says 'in a reasonable amount of time'.

My ex spouse threatened me that he would not pay my cobra insurance if the taxes weren't send to the CPA even after we verbally agreed on a date I need to have them done and I actually had them completed two days before the date, then emailed them to the CPA. He mailed the first payment for January 4-31, 2013 cobra insurance and the cobra insurance never became active since it was received and processed by cobra the on the January 31 payment two is due for February 1-28 and he is refusing to pay until March 2013. I can be reimbursed for any medical treatments or medication but unfortunately I can't afford the out of pocket expenses which he is aware of. He is now threatening to cancel my son on car insurance because the title has not been changed over but that wasn't a stipulation in the divorce decree. I have no idea what my legal rights are or what I should do. I am planning on changing the title over but I do not have the funds currently to do so. I am in the process of looking for employment, I was a stay at home mom for the past three years so things like the title can be taken care of. I did not have a lawyer represent me for the divorce because I could not afford one nor can I now.