MacOS – WD My Passport 0820 USB HFS+ data disk drive partition problem following accidental use of Recovery Assistant

I have edited this post in view of recent developments

I have a 2 TB USB Disk used for all my data. I accidentally ran Lion Recovery Disk Assistant on it, instead of my Pen Drive, to make a bootable installer. Now I can't mount the disk.

Disk shows up in Disk Utility

Now surprisingly one of the folders showing up from the corrupted USB HD 2TB but the folder is empty

Last login: Mon Jul 18 14:48:54 on ttys000
bash: alias: ll-ls -lahG: not found
sanjeevvyas$ diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_HFS MacPro HD 250.1 GB disk0s2
3: Apple_HFS Blank 650.0 MB disk0s3
/dev/disk1 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.0 TB disk1
/dev/disk2 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *1.0 TB disk2
1: EFI EFI 209.7 MB disk2s1
2: Apple_HFS ELEMENTS 999.8 GB disk2s2
sanjeevvyas$

Ideally /dev/disk1 should have the same partition structure as /dev/disk2 .I am missing 2 partitions, is there anyway I can fix the partition structure?

I have tried TestDisk, Data Wizard and Disk Drill, however nothing has helped.