Lost space due to iPhone restore?

I recently restored my iPhone 4 from backup and I noticed that it wiped out my computer's space clean. I went from having 6GB free to 202MB free space. I want to know, how can I get this space back. I'm on a PC not a Mac.

Thank you.

Added (1). Do I Really need to delete the backup for this?

Delete the backup.

Go here:

http://osxdaily.com/2012/05/04/delete-iphone-ipad-backups-easily-within-itunes/