Since she has sent a clear signal that she is attracted to you, your response should turn on whether YOU are attracted to HER.
You have stated nothing about whether you like her, would like to know her better, or date her, or whether she is attractive or hot looking. Those things should tell you how to respond.
It comes down to that because this was NOT some request to keep open some channel for some post-employment job networking. Not at all.
AFTER she has left the organization, you should feel free to ask her out.
However, I from my POV I DO see a slight red flag here. Mention of the recent boyfriend breakup could mean she is on the rebound and not thinking too clearly, or worse, she could be needy, clinging and desparate.
You could go and hit it, if she is really good looking and hot, but it sounds like you could get be getting mixed up with some drama queen with more baggage than the airport, afterwards, if you do.
It is your call, as the signal has been CLEARLY sent to you, and the next move must be yours.
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^^^^^^On second thought, never mind all of that.
Having passed up a similar chance like this (perhaps very wisely!) with your older boss, that you told us about, fate has now offered you kindly another, second, chance: And they don't come to people that often, either. So this time,
.
Just go and bang it like a screen door in a hurricane.