[ubuntu] Partition help!

Hey everyone!

I'm trying to install Ubuntu as a dual boot along side Windows 7 Starter on my Asus EeePC.

I've created a Ubuntu Live USB that I can boot to, but I am not able to create a partition for a full install. When I try, GParted tells me "It is not possible to create more than 4 primary partitions."

My netbook has 1 HDD, and under Windows it shows it having 2 drives - one with Windows installed, & another with just data.

Here's what GParted comes up with:

sda1 - ntfs - 100GB - boot (this is the Windows partition)
sda2 - fat32 - 15GB - hidden
sda3 - ntfs - 95GB - (this is the data partition)
unallocated - 90GB (I created this in Windows Disk Management before booting to the LiveUSB so I could create a new partition here...)
sda4 - unknown - 16MB (According to Windows Disk Management this is an EFI System Partition, whatever that is)

Is the data partition meant to be a primary partition? I thought it would just be extended...

I know my EeePC has some fancy fast booting things that I assume account for one or two of those primary partitions.

Any ideas how I can create a primary partition for Ubuntu to jump into?

Thanks in advance!