Personally I'd leave her to sleep. It sounds like the breastfeeding is more for you than her. Sleep is important for growth and development - she will be getting enough nutrients from her diet so the breastmilk is less important. She has the rest of her life to be woken up, first for school and then work, let her sleep her full quota while she can.
I'm wondering what to do about my DD's morning BF. I currently feed her morning and night and I wanted to carry on with this until she is at least 2. I've just started a new job which means leaving the house earlier so I have to wake her up earlier to feed her. At the weekends we leave her to wake up naturally and she generally sleeps for around 12 hours. I work 4 days a week and have to wake her up after 10.5 - 11 hours sleep to feed her. If I dropped the feed she could have an extra 30 mins sleep. I would like to continue the feed and she still seems to want it but I feel guilty about waking her up early as she looks so sleepy! She's fine once she's woken up properly but I love my sleep so I hate feeling that I'm getting her up too early. I'd find it useful to hear other people's views, what would you do - keep going with the feed, or drop it so that she can have a bit more sleep?