17 Month Old Won't Stop Breastfeeding!!

I breastfed my son until he was 14 months old (when I found out I was pregnant with my daughter). My husband helped wean him off of night feedings by giving him cow's milk while I slept in a seperate bedroom. I am a stay at home mom now and my daughter does not take a bottle whatsoever! Her night feedings have gotten worse and she wakes every 2 hours. We are not having anymore children and I've been breastfeeding for almost 4 years!! I want out!!!! Any suggestions ladies?? Oh and my daughter hates cows milk!