partitioning - Extending fourth extended partition to occupy more space

I've got four partitions on my 250GB hard drive:

1. (primary /dev/sda1, NTFS) Windows 7 Recovery partition (17.05 GB)


2. (primary /dev/sda2, NTFS) Windows 7 Boot Menu (100 MB)


3. (primary /dev/sda3, NTFS) Windows 7 OS


4. (primary extendd /dev/sda4) (80 GB)


5. (secondary /dev/sda5) Linux Swap (6GB)


6. (secondary /dev/sda6) Linux / (Ubuntu 12.04 LTS) (74GB)


7. Sucker unallocated space (70GB)

Now, since I've already created 4 primary partitions, alas,
I cannot create another primary partition at the end of the disk.

Is there a way to expand /dev/sda4 to suck up the remaining 70GB
so that the whole secondary partition ends up being 150GB?

I've tried the Linux gparted tool, booted from a USB Linux Live disk,
but no luck.

Seems like the only solution is to delete the extended partition
and recreate a bigger one that uses the whole remaining disk space.

Could this problem be overcome with other tools, say partition magic
or something so that /dev/sda4 is resized so I don't have to reinstall
everything from scratch (luckyly didn't have much on my Linux partition).

Regards,

John Goche