technically you will never find one...
the reason as such,
1) lay is some one that never taking the ordination vow only the
refuge vows
2) lama is someone that had taken ordination and taken the 3 yrs
retreat and judge by his own teacher that he is qualify to teach,
so granting the title lama, without they are known as
venerable.
so, 1 and 2 already cannot match...
Unless you asking for any lay female teacher that teaching
buddhism in sg.. Then I beleive there is...