id wait for the oppurtunityy-maybe when she says 'im not hittin on u' or soemthing similar again
and just let her know.say something like
'i know youre not ****(name) i love been freiends with u but if u ever did want to take it further i would love to! but dnt get me wrong im quite happy been your friend! jus felt i had to let u know i like u!
that way shes under no pressure (pressure often makes women run the other way)
yet shes aware the oppurtunity is there.and also you are not giving too much away.tellin her you are madly in love with her n think shes the only one for u etc etc can make u sound too full on.this way she is aware, but there is stil mystery about ur feelings
JMHO