( you said you see each other at the hall right? ok thats perfect )
So, do you think I should wait for an opportune moment in the hall, or do you think I should go to her office and talk to her ?
Alsol you said to ask her something like " we've known each other for a while now and i would like to see if you could come after work today for a cup o coffee, if thats ok with you? "
How about ice cream? Also... What do you think about a movie, or would a movie be a bad idea?