Sounds similar to how DD2 was, I'd attempt to put her down at 7:30 and she'd see it as a nap and be awake til 11ish. Eventually she caught on, we didn't push it, we just stuck to our bedtime routine of bath, cuddle and feed then bed. I can't remember what age she did start sleeping at good time but it did happen! In the meantime I just would sit up in bed, have her on my lap or next to me (she slept next to me anyway for months) and we'd just watch tv or dvd.