hiya,,,
how much does she sleep in the day??? it can be difficult to get children into a routine to suit your every day needs but it is possible?
im assuming she is having a nap or 2 in the day? so as hard as this will be ill try and keep her up for a whole day, maybe not do too much playing as she will end up falling asleep but surely by bedtime she will be soooooooooo tired so will sleep for hours and gradually get into a routine, obviously at that age they have a nap in the day 2, try get her to have her daily nap as early as possible, the more tired they are by bedtime the longer they will sleep
good luck , let me know how it goes :o) x