My opinion: She could be into you - but you'll never know unless you ask her out - could be something as simple as going to the park or on a hike (if you like outdoor activities). Seems to me like you know her pretty well and could figure out somethign low-key to do with her that doesn't involve your work-place... a good, get to know you better sort of thing.
Go for it!! Otherwise you'll never know!
