MY DS1 was 22 months with DS2 was born - i moved him intoa bed at 18 months...
You could prob buy some time using abasinetter for baby until your older one is old enough to move?
I bought a 2nd monitor and also a few things i didnt have with DS1 that i wished i did
I also got a new nappy stacker so i could keep nappies seperate on the chg table
I foind i needed to organise things lke vhg table, nappy bag etc a lot more to keep things seperate
I also got a good sling so i can carry DS2 and push DS1 in a stroller
And I just bought a great double pram whvih is a lifesaver (I got a mountain buggy)