Bring your guts, go to her and talk. Sae on the bus, then get a
chance to go to her and chat. Best if she siting alone and you sit
besides her.
Say, "Hi." She replies back. Note her behaviour towards you. Then
talk more... like, "I noticed you work in the same building as me.
How is the work there like?"
Depending if shes comfortable answering you or wat, you will know
it through her repiles and gestures. Strike out more words. Dun
instantly ask for her contact though. Wait for another time before
you leave. The next time you go to her and chat, depending on how
she reacts, you can then ask for her contact, msn or whatever.