Since u've cleared ur grp1 in may 2012, the earliest CAfinal attempt u can go for is may 2015 as u will be required to complete 2.5yrs of ur articleship training. Also for giving this attempt u must register for articleship latest by 31st Oct, 2012 because as per the ICAI guidelines one must get registered for articleship within 6 months from the month of their ipcc exams, to be eligible for the earliest final attempt.
Nd yaa i guess its alryt if u complete ur itt and orientation training during these 2.5yrs period as one is required to get registered for final exam atleast 9 months prior to appearing the exam. Also note that for registering urself for finals u'll need to submit these 2 certificates, hence its concluded that u'll have to complete these two trainings before 9 months of exam atleast and obtain the certificates for the same.
I would advise to complete them at the earliest possible.