Breast to cows milk

Or should I just try and pump and give it to her ?

Dont do cows milk. Do kendamil which is goats milk formula/ already made milk as its much better. Kendamil is good but cow and gate, SMA gold etc are bad for your child health. Use kendamil

If your Little one has had bottles before the easiest transition would be to combine milk with your breast milk in a bottle and slowly up the amount of milk and lower the amount of breastmilk gradually, you could always just try a bottle of pure milk as they may like it