I had a 27 month old, a 1 year old and a 1 week old and it was very hard, but in a few weeks it'll all work out for you.
Really.
Just organize (or have your hubby help) as much as you can the night before. Consider moving your life to one room... the one right off the kitchen... for a month or two. Keep diapers for both there, with changes of clothes for the kids, a playpen or cradle, toys, etc. And keep your clothes you're going to change into (think "sweat suits in varying colors"... velour is nice this time of year) nearby, like the downstairs bathroom, along with a scrunchie for your hair.
Showers? That's really what those baby wipes are for and make use of them! Keep a minimum of make up downstairs... foundation if you feel you need it, but I always figured mascara was the actual "necessity" for most of us. Lip balm. Eye liner. You're done.
Food? Well, toddlers must eat, so try to get a weeks worth prepped and in Tupperware on Monday. Your baby is nursing, so that leaves you... Lean Cuisines are good and you can make and eat them with one hand.
Snugglies... I don't know what they call them now, but I would often wear my newborn around the house while I did the minimum of picking up, washing clothes etc.
Grocery shopping was an adventure with 3... I wore the Snugglie, put the 1 year old in the seat and stuck the 2 year old in the cart. There wasn't alot of room for groceries but it cut down on spending!
Really try to focus your life in kitchen/den/downstairs bathroom area. If you are all one floor that's even better, but still condense to one small area, and make your life there.
It'll all work out and if you send your two year old away,wait a few more months, so she doesn't feel like she's a burden.