Time Machine Not Being Recognised

Hi there,

A few days ago, my 2TB Western Digital 'My Passport' was working perfectly. I have two partitions on it, the first 1.5TB for my general use and the last 500GB for my Mac, to act as a Time Machine. Both partitions have been working fine until a couple of days ago when the Time Machine partition could not be read by my Macbook Pro. Whenever I connect my Hard Drive, it pops up with a dialog box saying "This Disk Could Not Be Read By This Computer" - or something along those lines - and it gives me 3 options; Ignore, Initialise and Eject. If I click Initialise then it will open in Disk Utility and give me more options. I click on the 'Verify Disk' and it gives me many errors, and it won't let me repair the disk so I just tend to click ignore now. I need to know how I can fix this issue without losing everything on my hard drive, including my personal files on the 1.5TB partition and the current Time Machine back ups that are already on my Hard Drive.

Any help would be appreciated,

Thanks