WD external Hard Drive comes up with "The disk you inserted was not readable by this computer."

So here lies the problem, when connecting my WD external HD to my MBP, I get the message The disk you inserted was not readable by this computer. and a further three options of initialize, ignore and eject. I have always hit ignore.

When checking my files, the HD is not available in my finder window.

I've gone into Disk Utilities. It is there to be highlighted. And I go to repair the disk, but each time the Repair button is greyed out.

I've tried to use my data recovery software (rescue pro deluxe) but because the drive isn't showing up in that program, it isn't working.

Are there any other options out there to get the files from that HD (I've just gotten back from 2 months of travel with a bunch of photos on that HD - so would like to get them back). Even if that means putting them onto a spare external HD.