Mandatory conversion from pcc to ipcc

I have passed PCC Group 1 in this attempt (Nov 2012) but couldn't clear Group 2.
If I have to register for IPCC, do I need to write all the subjects once more ?

No. You will have to appear for the remaining subjects under IPCC Units Scheme.

What time it takes for registration and can I appear for May 2013 exams ?

You can appear for May 2013 exams, if you have completed your ITT training and articleship (technically 9 months completion is required). But being a PCC student, i presume that you have already completed the above two.
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You can convert now into IPCC/IPC

> Download Conversion Form

 https://220.227.161.86/14650IPCC_Converson_Form.pdf

> Rs. 500/- draft (in favour of “The Secretary, The Institute of Chartered Accountants of India)

> Attach copy of ITT Certificate

> Attach copy of Article Completion Letter

> In some branches/regions they are also asking for copy of Class 12 marksheet.

> You will get latest study material applicable for IPCC students.

Thanks