I think it means that she wants to get back together with you - but she might only be thinking for a fling, since you mentioned she is seeing someone. I would ask yourself if you're okay with that - because if you actually have feelings for her, it will only be worse if you do hook up and nothing happens after that. Plus, if she is flirting with you and talking about drinking (and more) while she is with someone, if she dumps him to be with you, what's to say she won't do that to you in the future? Just my thoughts. Good Luck!