How can I give space of dev/sda7 to dev/sda2 Huh?
You can do this, one procedure looks like this (basically).
Run Gparted fron a liveCD
Move/resize sda7 (/home) to the right.
Move sda6 (swap) to the right.
Move sda5 (/) to the right.
Resize sda3 (extended) to give the free space.
Resize sda2 (windows).
Although, if you are not confident with Gparted, or don't have everything you want to keep backed up (you should, partitioning errors are only one way to loose data), I would not recommend it. Even though it would mean no changes needed to bootloaders.
An alternative that minimizes risk is
Run Gparted fron a liveCD
Shrink sda7 (/home) to the left by the total amount needed for windows.
resize sda3 (extended) leaving free space at the end of the disk.
use the partition copv/paste function in Gparted to copy sda2 (windows) to the free space created.(which will become sda4)
resize sda4 to use the remaining space.
Reinstall the windows boot loader,.
Once you are satisfied with the sda4 windows install, remove the entry in the windows bootloader for sda2.
reformat sda2 to use as a data partition.
Edit or reinstall GRUB.