Have you tried putting her in her cot for the first part of the night? We co-slept too but at this age I would put them in their cot for the first part and then bring them into bed at the first wake up. Otherwise I would wake them when I came to bed and they were restless. I found this way we could get a good chunk of sleep for the first bit (sometimes, LOL) and then still co-sleep when they needed it for the second half.