grub2 - Which partition to select as device for boot loader in an EFI mode install?

I'm trying to install Ubuntu 13.04 alongside Windows 8 (to dual boot) on my new laptop.

Since there is already an EFI partition on the disk, I didn't create another one (as suggested in: https://help.ubuntu.com/community/UEFI#Creating_an_EFI_partition) and I selected /dev/sda3 as the device for boot loader installation. After the installation, ubuntu worked fine but I couldn't boot into Windows 8 (when I select the win8 in Grub screen it gives an error message). I restored computer to factory state using recovery and now trying to install ubuntu again.

Which partition should I choose for "Device for boot loader installation"? Thanks for the answers.

Harddisk is partitoned like this: