I agree with adgal. My daughter was not fully potty trained until she was 4. We let her take it at her own pace and didn't make a big deal out of it. We used a candy potty reward system for at least a year before she got it. She was also allowed to have her portable potty wherever she wanted to in the house. For a while it was in the living room. We then moved her onto one of those cushy kid seats for the big potty. Eventually I had to throw that away though. It just got old and gross. Just relax and let her do her thing, which is to primarily play and be a kid! :)
Wow, she is in kindergarten at 3? Can she not go there in pull ups? We have started working a bit on potty training so I have been reading an awful lot on this lately. Its really not uncommon to not be potty trained at 3 and every child is different. It's also not uncommon for even fully potty trained 3 year olds to not be comfortable going potty away from home. It's a bit scary for many of them. Everything I have read and heard on the subject say's to allow them to take their time. Pushing them creates a power struggle, and can make them feel a huge loss of control which just makes matters worse. I would leave her in her pull ups and encourage her, but not push her. Best of luck.