My 4 1/2 month old's sleeping schedule?

Ok, she takes maybe 2 naps a day, maybe an hour at the most... but she doesn't fall asleep until anytime around 1-2 maybe not even til 3:30 a.m. but she'll sleep on and off for 12 hours after that. So if she falls asleep at 2, she'll sleep until about 8am, wake up, eat, get a diaper change, and fall right back asleep until maybe 4 hours later, and wake up, eat, diaper change, and back to sleep and continue that for about 12 hours, so she doesn't wake up for good until around 3 in the afternoon, therefor her naps don't start until about 6, then another about 9, (give or take) We try to bathe her around 9 depending on what time she's napping, how can I get her on an earlier schedule? I don't want her to be real cranky from us having her stay awake longer, but if we have her get up earlier and go to bed earlier she'll probably have to wake for a feeding, like if we try to get her to go down at like 8-9 for the night she would probably wake up about 3 am because that's been 7 hours..... I don't know, any advise would be great, please! Thanks in advance!