How to go about this relationship?

Alright, I just got out of a 2ish month relationship with a girl I work with. It ended...well I suppose, no hard feelings, it was pretty much FWB anyway.

Now there's another girl I like a lot, I used to work with her and I took her to grad. Well end of May was her birthday and I went out clubbing, we made out that night and slept in the same bed. Just a few nights ago I hung out with her again, we actually slept together this time. I texted her and she said that was a bad idea, not that it wasn't fun but that she cared about me. How do I turn this into something a little bit more meaningful now?