My children are about 20 months apart, and when my daughter was @ 3 months, I think I put my son down first. He went down about 7-7:30. I THINK I would just leave her in a swing or pack n play in the other room. Sometimes she would scream and cry, but most of the time, she was good for the 10-15 minutes I needed to rock and get my son down.
Now, they are 1 and almost 3. I put my daughter down first (@ 7:30) which includes nursing and rocking. My son watches TV and eats a bedtime snack in the other room. This is the only time he gets to watch TV, so he is normally enthralled.
After she goes down, I I get him in jammies, read him a book and put him down, @ 8:00.
The post 4:30 time is always rough. Especially with a little baby. My son watched ALOT of TV for a while, because it was the only thing that could keep him out of trouble while I was feeding or bathing the baby. Hang in there for a few more months and it gets lots easier. Once your little one can self feed, meal times get easier because she can spend 30-45 minutes eating little pieces of food. At about 8 months, I started putting her in the bath with her brother, which also makes things easier.
Good luck!
Ps - dont worry about chores for a while. Just have a messy house and wear dirty clothes. :)
Also - to help with the post 4:30 cranky babies - go outside. My kids both love being outside. I would throw something in the oven for dinner - fish sticks, sweet potato fries, etc. and then play outside with the kids until it was ready.