12.04 - Help needed with deleting a Ubuntu partition

I have a question about my partitioning.
Some months ago my laptop crashed, so I decided to put Ubuntu on it.
Because I had some experience with Ubuntu 12.04 LTS I choose to create a dual-boot with Ubuntu 12.04 and Ubuntu 13.04.

Since I never use Ubuntu 13.04 and my Ubuntu 12.04 partition is running out of memory I want to delete the 13.04 partition.

I am a newbie with these things, so I hoped you guys could help me out.
How can I delete the 13.04 partition without losing data from my 12.04 partition?

A screenshot of Gparted:

How can I see which partition contains which Ubuntu version?
And what about the swap partition?

Thanks in advance!