I am no love guru ah..but my advice would be that perhaps you
could just ask her out for lunch or dinner in an impromptu
manner.Let's say just jio her out for dinner as you two are leaving
the workplace, considering you know her liao, this shouldn' seem
too awkward. Don't think of it as a date lah, just like going out
with friends first. Then from there , see how things work out. It
would prevent the awkward feeling of asking her out on a
"DATE"
Good Luck!