I have had this happen to me before and I emailed the seller and politely told her that I have already paid the amount according to the auction and I would like the item that I won.
She is not allowed to raise the price. If she wanted more money then she should have set a higher price to begin with. Don't pay her any more money!!

She has violated the ebay rules by even approaching you for more money. Before leaving any feedback, get in touch with ebay and launch a dispute. They are very helpful and will let you know what your rights are.

If you really want this pram, then follow it through. The rules are on your side.