extension of articles-please help

friends...Currently i have cleared pcc group 2 and will be giving group 1 in nov 2009. and my final attempt will be due at may 2011. I have taken almost 6 months of leave in the foregone period of articles which is excess of allowed leave period. I have informed my boss that i will extend the articles after end of articleship term. Now my question is that maximum for how much period can i extend my articles as i will be taking more leaves in the future for tybcom and final exam. Next question is if i extend my articles will my final attempt will get postponed??????????.pls reply....thanks in advance