So I have a Windows DVD and it works. But when it gets to the part when it says "Upgrade" or "Custom" I click on custom and at the bottom it says cannot install over it because Windows 7 can only be installed on an NTFS drive? I know that Ubuntu formatted my partitions into one big on that's an ext4. What can I do?

I know that I can maybe create a 30-50 GB partition that's an ntfs then when I go into windows I can format the Ubuntu one and combine them but I don't know how to make a partition much less make a big partition in the "GParted" program? So any ideas would be very helpful. I know how to do anything with a hard drive using the default program that comes with Windows 7 but I feel like a mouse in a maze when I open GParted.