i have the same issues Its quite difficult it is getting a bit better though now dd3 is 9 weeks. My older girls 3 and nearly 5 dont really sleep during the day most the week, but the day after kinder (ie today) they will fingers crossed. I give them quiet time in their bedroom, Also at night when your new DS goes to sleep you should sleep too, thats the only way I can get enough sleep, dd1&2 I put in their bedroom at 7pm, dd3 has a feed then and I put her to bed in her bassinet beside my bed at 8pm, and I go to sleep myself at 8.30pm and she doesnt wake for a feed until 2am now which is good so thats how I get most my sleep. Then she wakes again at 5am and thats it for the day I have to get up cause after I feed her dd1 & 2 get up... so my days start at 5am at the moment.