Maternity Benefit - Self Employed Contributions??

Hi, a friend who is self employed needs to know asap how much she needs to have paid in PRSI contributions for 2009 in order to claim maternity benefit?? The SW told her she needs 52 wks contributions but what she needs to know is how much this is exactly?? Many thanks..

PRSI is paid as a percentage of earnings; See here for 2009 rates

Thanks!