My Employer filled my Green card in EB3 category instead of EB2.

I have 5.2years of IT experience and education B,Com and MBA(PG, its masters in India 3+2 years, total is 17 years of education(including +2) from India.

Qn1) am i eligible for EB2 from EB3 ?

already applied for PERM(labor) on Feb-01-2011 and got approved 07th Feb-2011.
Qn2) now i have to start the process for I-140, when can i change my Green card process from EB3 to EB2 category ?
Qn3)can u pls let me know the process and at which level i can change the process to EB2?
Qn4) am i eligible or not for changing to EB2 from Eb3 and wht is the process ?



Thanks,