If you want to get her something, I would say do something like put some real effort into making your own card for her. If you buy loads of flowers and chocolates it may be a bit too over the top and scare her off.

I'm not sure how she'll react. It's good that she liked you before you dated, that could mean that she still likes you now but is just scared. But not wanting to hang out with you is a bit of a bad sign as it seems she isn't all that comfortable about being alone with you.