If you will have more questions please provide output of following:
1) Hmm... first of all... if you want to resize partitions all that partitons must be unmounted. Thus you need to do that from windows or (better option) from some linux live cd. Live cd will allow you to unmount every partition on your disk and resize option should be available. This is general rule for some serious operations on drives - serious operations usually needs unmounted partitions.
sudo fdisk -l /dev/sda
sudo parted /dev/sda print
2) Resizing partitions, if they contain data, can be very long. I remember that once it took one night and one day! Thus much better approach would be to borrow some empty disk, copy whole data and then clean partitions and resize/merge or better just perform new installation.
3) In such situations, where merging partitions causes that one partition will be removed and other will be renumbered, can lead to problems in booting you linux. Then you will neet to start live cd and correct /etc/fstab and maybe update-initrams -u -k all. Looking at your /dev/sda list I guess that this case should not touch you.
4) Resizing/merging partitions is serious operation and can be interrupted due to some errors. Thus state of partitons can be unknown which will propably need to reinstall your linux.
5) If you want check 2) and 4) just plug some big ~8GB flash drive, make few partitions (primary/extended/logical), fill it with some random files... and play with gparted. And hdd operations takes much more time than on flash drive!
6) The option resize/move is also not available as I guess that sda7 is a logical partition (within extended partition) and sda5 is primary partition. Thus you need to remove sda7 partition, then you need to resize/shrink extended partition that previously contained removed sda7. Then free space will appear to extend sda5 and resize/move option should be available. But to be sure look at "sudo parted /dev/sda print" output or at gparted. The trick is that to resize partition there must be empty space. So you need to shrink (resize down) some other partition or just delete them.
Please backup your data. Despite gparted is super toy I usually had serious problems using it.