I would say, if you have reached that point of desperation, to...
set a bedtime convenient for you, we have chosen 7pm as it gives dh an hour with dd when he comes in, but it gets her out of the way so we get an evening to ourselves,
then...stick to it! following a little routine can help
ie bath, story, bed...
but you have to stick to it!!
(we found night time bath didnt work as it excites her so much, so she has a morning bath)
I dont know how you are feeding, but you can cc at 11 mths can sleep for the whole night no feeds, so leave to cry for 1 min, then go in and say ssshhhh
then another 5mins, if still crying, say ssssh
then 10 mins , say sssh from the doorway ETC
then see how it goes, slowly am waking should get later, esp. as darker in early mornings now,
then through the day get used to waking the baby up to keep the nights smooth if neccessary..
30min nap about 10/11am
approx an hour nap after lunch
30 mins nap no later than 5pm
there are lots of books available that can help, it takes 1week -2wks for results so you do have to grit your teeth and be determined, but at the end of the day a happier mama = a happier child.
hope this helps, best of British