Hello N., This is a hard one. My situation is a little different since one of mine is a teen. However, I found that he wasn't getting the time that he deserved. I would say that the best thing that you can do is let the little things that don't matter, go. Set up a cleaning schedule so that you don't feel stresed about it, have the kids pick up their own stuff (even my 20 month old responds to a clean up time song we made up and will put his hot wheels back in the box). The older one can help you cook, set the table, and unload the dishwasher (this will be alone time with him/her, since it's something the very little ones aren't doing with you.
You can include them in helping to take care of the baby, they can be in charge of handing you wipes and diapers, or talking quietly to baby while you change the diaper. You can read to the two older ones when you are nursing the baby.
They might need less "alone" time with you than you think, just make sure that you leave the baby with hubby and go outside and make a snowman with them, or color, etc. When you are feeling really overwhelmed with the house and the baby, etc, just give up and sit down and play with the older 2, it will be a breath of fresh air for all of you.
Don't forget to take care of yourself too. Do the grocery shopping when your spouse is around so you can go alone, stop at the coffee shop and read for a hour, while you are out. Once a week, go spend time wiht a friend (I joined a knitting club, and now for 2 hours every week, I am with other women, talking about life, I didn't know how to knit when I joined, they will teach you and be happy to do it).
God Bless.