Not sure how to combine unallocated space? Are they consecutive area? Do the fdisk -l again and check the 'Start' and 'End' numbers. If you don't have a menu.lst, your install didn't finish but that doesn't matter as you've deleted and will re-install. I'd carefully read all the options about where to install during the process. The one thing I would suggest is that you install the ubuntu bootloader (Grub) to the master boot record as it is easier to boot windows from linux/grub than to boot linux from windows.
Here's a site explaining how to boot Linux from windows if you choose that.
Linux.com :: Convert a Windows system to dual-boot Linux on a second drive
With ubuntu/grub, grub should detect your windows system and put an entry in the grub menu.lst file for windows and enable windows booting. Read carefully before making selections in the install!
A 5GB partition will be pretty small for ubuntu unless your just planning to check it out and not really use it.