Hi monkeysmama
The carton milk is much sweeter than the powdered variety and my dd preferred that too, but she did take the powdered version after a couple of goes. Try the morning milk feed first as your dd will be hungry and thirsty so hopefully more likely to take it - this worked for my dd.
In theory it is ok to go straight to full fat cows milk, but my dd like a few of my friends toddlers who were also bf upto and beyond a year, found that the cows milk gave them wind, so introduced it very slowly in small amounts at first, eg on the breakfast cereal.
As for quantities, my hv said she should be having up to 20 oz a day - no chance for my dd she just doesn't have that big an appetite.
Hard to tell if you are still bf - how many times a day are you bf? Try making up a few oz at a time, if she finishes it quickly, make another couple and so on till she doesnt want any more.
Word of caution though, too much milk can suppress appetite for solid food.
You have done fantastically well to bf for 13 months, maybe if you are introducing other milks now, it would be a good time to stop and give yourself an end to the expressing!