I think my top tip would be, lower your expectations! I've got ds, 2.10, and his 12 week old sister. It feels like we're just coming out of basic survival mode, but we survived!
In my experience, a lot depends on what sort of baby you have. Mine won't sleep anywhere except on someone, so a sling has been vital. She's a big baby though so our stretchy wrap only suited for the first weeks and I've now hired a soft structured wrap from my local sling library. Def worth checking out.
As for how to occupy the toddler, unfortunately the telly holds ds attention for about 2 minutes, so things like reading, playing with train stuff, and generally pottering seem to work. Out and about is a bit more challenging and I've had to leave ds strapped into the buggy whilst feeding before. He wasn't impressed, but he was safe.
Get a cleaner if you can afford it, get someone to batch cook for you, or get ready meals for a while. Marks do great toddler ready meals I've found :) take any offers of help, you're still recovering from the birth and need to rest, even if you don't feel you do!
In our family dh has basically taken over the majority of toddler care while I'm doing all night feeds etc. He does the 6am stint and does bedtime, but we're lucky in that he works from home.
Finally, in a couple of weeks, try to get out the. House at least once a day. Going to other people houses in similar situations is a life saver and much easier than traipsing into town or whatever. And get a double buggy even though I'm usually found pushing it whilst wearing the baby! as they're invaluable for toddler dumping!
Congratulations :) even at 12 weeks her brother is already trying to involve her in his play, and it's heart meltingly sweet to watch and almost makes up for all the tantrums