RE: 13 mo old won't use sippy cup!
Here's another vote for the TakeNToss cups. They were the first ones we used successfully.
Another thing to try is putting something she already drinks in it (breastmilk, formula, whole milk, whatever) so that she knows that what comes out can be swallowed. We used water at first, but my DD just didn't get that you swallowed the stuff from the cup. Then one day I tried formula, and she understood immediately.
HTH,
Beth, mom to older DD (8/01) and younger DD (10/06) and always missing Leah (4/22 - 5/1/05)