It may not end up in plaster but you'll definitely need it to be immobilised so using that arm is going to be out, I'm afraid, sorry! Hopefully your fingers will be free but you won't be able to take any weight through it.
A sling could be your friend, if it's one you can put one fairly easily (no long wraps etc)
Try and do things at a higher level, such as can you bathe her in the sink? Is she in a cot or a moses basket? Whatever you use make sure it's high enough so you can scoop her up with your right arm.
I've got a changing mat with straps (Rabbits, from Amazon) as I have a very wriggly child, but they are good for people who can only use one arm.
For feeding, boob or bottle, use a feeding cushion that you wrap around yourself (Mothercare, Argos) so your DD is rested on that at a decent level, then you only need one hand to hold the bottle / positon boob!
A rubber mat on your kitchen worksurface means that you can press down bottles / jars etc using your right hand to stabilise them before you undo / tighten up the lids.
Dressing her in clothes that have less poppers will be easier.
If I think of anything else I'll come back to you. Good luck 
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