regimen comunitario

Hi,

I am indian nation and get married with spanish girl in 2005 in ireland that time we both was working in ireland. We get divorced in 2012 and before divorce i got my 10 years residency card from spain.

1.As i am divorced now do i need to change the residency card which i have for 10 years.
2.I dont have a job in spain so i am getting some job offers from ireland is there any type of id available in spain which can grant me permission to work in ireland or in other EU states.
3. on a marriage base is i am eligible to apply for nationality yet or not.

please suggest me.