When Josie was a baby (WOW, so long ago!
and I was starting out extending her awake time, I did it in tiny increments. I'd take her back to her room before she would normally show her tired signs and we'd change her if needed and play back there. I'd just play with her and a stuffed toy or a diaper cloth in dim light till her eyes could barely stay open, give her a snack feed (this was partly related to the 3-month growth spurt), and put her down.
Also, is your DD waking around 4AM? If so, can you get her back to sleep w/a dummy/pacifier? Maybe use wake to sleep if there's a habitual waking then? Maybe yu can get her to sleep through that and she'll wake for the day w/o being so tired - at least that's how it worked for us. We had to introduce a dream feed for Josie to get her through that waking w/o feeding her but it helped. Natalie, on the other hand - we had to STOP the DF because w/o it she sleeps till 3AM but with it she wants to wake at 5AM for the day :shock:, so it might be a matter of trying different things and seeing if something clicks. If not, odds are that in another couple weeks the naps will extend on their own, as will the Awake time, but if you're looking for results NOW, check out the Announcement at the top of the Naps board about Josie and her 45-minute naps. Tracy gave us lots of good info, and even though it was 3-1/2 years ago, I managed to get the info down while it was still fresh, so it might be helpful.