ilr and maternity leave query

hi i would be grateful if i can get some more information on my status at the moment.i am currently on the old working permit system since 2008 and im due to apply for my ilr in april 2013.i just had a baby in may and im on maternity leave since april and i would like to know whether this will affect my indefinite leave to stay when i apply as i am thinking of taking up to a year of maternity leave.the problem is that my company only pays three months up to 90% and the further 6 months will be from the statutory maternity pay. do i need to go back to work after the 9months or i am allowed to take more unpaid maternity leave. Also my question is will this one year gap be taken into consideration when applying for my indefinite laeve to remain. any help will be greatly welcome.thank you.