It's not a party, will just see her one-to-one at work with no one else around. So a cold close is best option, eh
You don't want to entirely ignore her or anything. This would probably appear out of the ordinary and maybe even butthurt.
Instead, approach this in a business as usual type attitude. ie; "good luck with the new job" or with a "gee thanks, now we have re-train someone new" friendly smirk. I wouldn't say anything personalized to her.
From what you've written, she already knows that you had an interest in her. She's now leaving the job and with that she's taking with her a lost opportunity with you.
I don't want to offer false encouragement, but do not remove contact info for about a week. I say this in the event that she's not the type to mix business and pleasure. There's no need to send her any reminders. If she's interested, she'll initiate.... but again, I don't wish to throw out false encouragement.