How to approach this?

You can certainly count your blessings she's come back into your life just when you needed her the most, almost as tho it was meant to be! I am one who happens to believe things do happen for reasons. We may not know why at the very moment, but in time we usually find out. This just so sounds like the case with you two. Always too been a believer that we get what we need when we need it the most. This also sounds as tho it also applies to you. You can have an attitude of gratitude you now have someone to share in your life at a time when you needed it the most! For the short length of time she's been back in your life, she's proved she's there for you when you need her. You also seem to get along quite well together & do enjoy one another's company. It does appear she likes you more than just a friend at the moment anyway. I would say that only time is going to tell just how far this relationship seems to blossom. As it seems so far so good! For now keep things as you're doing & hopefully for the sake of both of you it does develop into something deeper for both of you...the very best to you...:)