I was staring down the barrel of three kids waking at night when I was pregnant with #3 - DS was waking once or twice, DD was waking with massive screaming sessions and I was 8 months pregnant. I ended up crying to the health nurse at a public latch on event lol.

I am certainly no sleep expert 'cos I can't even get my own kids to sleep but I would get her into a single/king single bed. Put her to sleep in there during the day, teach her to climb down properly when she wakes (my 13 month old gets off my bed after day naps). Send your DH in to resettle her/co-sleep when she wakes during the night. It will be a rough ride for a few nights as she gets used to DH settling her, but then it is easy (or at least his problem, not yours lol).

Have you tried a later bedtime? Sometimes it is better for the sanity to put them to bed at 9.30 and have it take 10 minutes rather than aiming for 8pm and taking an hour.