My friend, if a girl likes you, thinks you are cute, or is interested in you, SHE WILL let you know one way or another. I've had similiar responses. Here is your case (as happened to me) but with a positive twang.

So lets exchange numbers so I can get a hold of you later on.
- Ummm...My cell phone is sorta broken...So it barely works.
Me - Alright, well
her - (interrupting) - You know what, heres my screenname, and when I leave my dorm tonight I will be with one of my friends, so I will give you her number online once I'm sure which one is coming with me ok? That's easier...

Me - Okay, talk to you later

The above example illustrates at least a degree of interest on her part to talk to me.