Hi there
Glad to see you here and hope we can be of some help.
I do agree that your lo will start sleeping longer and I believe will start waking less at night if you move the feeds apart and lengthen her EASY. Right now your lo doesn't really have time to sleep due to being fed ever 2-2.5 hours.
At around 4-5 months 'most' lo, as stated by Aly Mac, are on a 4 hour EASY. Here is a sample routine for you (mind you this just a sample...each lo is a bit different and you'll need to piece together your own unique EASY...it may look just like this but it may not and that's ok too...they just usually have around 2 hours of A time and around 2 hours of S time, plus a cat nap)....
8am wake and feed
10-12 (1.5-2 hour long) Nap
12pm feed
2-4 (1.5-2 hour long) Nap
4pm Feed
6-6:30 Cat Nap (no more than 30-45 minutes)
8pm Feed
Bed
Of course you will want to move here gradually. I would move the feeds apart by 15+ minutes every few days (make sure her 1st feed of the day is a nice big one and then you'll know that she can go for quite a bit with out a feed..she may cry or fuss a bit at her normal feeding times but that's because it's what she's use too, not necessarily because she is hungry). Your lo will begin to be able to take more milk in at one time as right now she is probably full all day long from not having time in between feeds to really digest and start to feel hungry again (and with out getting full feeds she's isn't going to be set for the night, iykwim). With your lo getting more rest during the day, she will be able to sleep better at night (good day sleep = good night sleep). You can also do a Dream Feed at around 10:30 or so and that should help her sleep for quite awhile thereafter helping mommy get some good sleep too!
Let us know what you think.
Melissa
**Please also check out the feeding boards. There is a FAQ's thread at the top of each of the main pages (Breastfeed has one, bottle feeding has one, etc.). There is some great info with in the FAQ's that will better help you sort of the feedings.
Melissa