Me again!
Here's your grandmother's birth info:

Ireland, Civil Registration Births Index, 1864-1958
Name: Mary Christina Toomey
Date of Registration: Jan-Feb-Mar 1899
Registration district: Dublin South
Birth Country: Ireland
Volume: 2
Page: 665
FHL Film Number: 101067

This may be Lizzie:

Name: Elizabeth Toomey
Date of Registration: Jul-Aug-Sep 1897
Registration district: Dublin South
Birth Country: Ireland
Volume: 2
Page: 692
FHL Film Number: 101066

Cheers
Colette