Lost files WD 250gb external drive

I have been trying to free up my 500 GB Hardrive on my laptop Windows 7 to a WD 250GB usb hdd and I was also writing to an SD card well its ended up with only the SD card showing with files that were supposed to be on there only, now I can’t access the main files that was trying to back up. Is there any easy way to retrieve these files as I have a lot of video’s that I don’t want to loose
Here is what I have when I look in Control Panel Administrative Tools Computer Management Disk Management =
Disk 1 Basic 232.88 Online

229.25 GB Unallocated Which is where all the files that I want and can’t access.

I have tried EASEUS Partition recovery free and I can’t access the files

Try using TestDisk or Mini Tool data recovery software