If you can, try talking to your teacher about the issue you are having, and speak to your friend that s/he needs to get these people to actually do something.
I've had similar experiences. I had to do a decades project, we were assigned the 50's and we had to present a power point to the class for 45 minutes. since we were the 50's we had to go first, so we got the assignment on a Friday and it was due the following Monday. the group that got the "new millennium" got a week and a half to do their project. It wasn't fair at all.
we were also in a group of 4. two members didn't have time to come over and help work on it. I didn't sleep at all the night before(my friend said she was too tired to work and went upstairs to her room and fell asleep at 11) , and basically did the whole think myself.
and she wouldn't get up in the morning so we were late to class, and on Mondays the period is only 50 minutes, 45 of which we needed to present.
We had to include notes to give to the whole class, with blanks that they had to fill in from the power point. I didn't make our notes extremely long and there wasn't a ton of writing to do in them. My teacher marked us down for this. We were late, she marked us down, we didn't dress like we were in the 50's, she marked us down, our teaching section was more from memory than from the power point, she marked us down.
they next day the 60's group did the SAME EXACT thing and they got extra credit because it was easy to follow along with. everything we got marked down for, they got extra points for
we ended up getting a "D" she jacked my grade up (even though it was supposed to be the same grade for each person) because after class I told her the situation and what had happened over the weekend. She told me she understood that and felt for me, so she gave me a C-, and gave me an extra credit assignment that would make the grade into a C+, she also told me to study a certain part in our book because next class their would be a pop quiz, If i did well on it, I would get a B in the class (I had an A previous to this)
so next class with your teacher try to explain your situation, they might be more understanding knowing what the problem is as compared to thinking you guys are just lazy and don't care.
Good luck Kiri~