Toilet training 3 year old

[libertysilk]

My 3 year old (just 3 a few days ago) has been toilet training for what seems like for ever. She will wee on the toilet, but won't poo. She'll poo in her knickers, but has pooed twice on the toilet.
She's in the last few weeks starting weeing on the floor. Today once, yesterday twice.
I've tried using pull-ups, but, don't know if putting her in knickers is better. I praise her loads when she wees, even doing a silly wee wee dance.
I just want to accidents to stop.
Please, please can you help?