If you don't have a windows 8 disk or a recovery drive, in my experience PC makers these days will charge you the cost of an OEM licence to get your hands on 'installation media' for a licence you already bought, because they never gave you an install CD to start with. It's all a big con. First time it happened to me with Acer when I changed a HDD I decided to pay the extra and buy a licence from MS rather than give Acer a penny for their money grabbing tactics.
Anyhoo if like many windows 8 users your manufacturers didn't give you an install media, or even a licence key on your laptop, you can just reinstall ubuntu. or any linux distro. By the sound of it your windows installation is intact, so just reinstall linux. This will repair grub (at the moment you have an entry on your HDD that points to a partition you deleted).
If, as I suspect you were trying to remove ubuntu, and just want Windows on your machine, you can use any ubuntu live CD to do it. Don't install it, just click 'Try'. Once at the desktop, open a terminal and type:
sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install boot-repair
Once installed, start boot-repair and it will scan your system. Because you only have one installed system and a broken boot process the recommended action will repair the system.
Once that is done, open gparted and delete any partitions you forgot about - swap, extended, ext4 BUT DO NOT DELETE ANY NTFS PARTITONS (They are green). this will give you free space you can expand into in windows. Do not try and expand the windows partition here, just remove any remaining linux partitions and click on apply (the green 'tick')
Then restart, that's it!