Disk utility deleted all partitions! (External HD)

I used disk utility to get rid of just one partition of an external HD (I had four) and it deleted all of them! is there any way to recover the data?

The bad news, which I guess you already know, is that Disk Utility can't selectively delete or merge separate partitions, it is all or none. The good news is your data is not really gone, but it is going to take a bit of work to get it back. My favorite is Data Rescue II:
http://www.prosoftengineering.com/products/data_rescue.php
Other people like SubRosa which I have never used:
http://subrosasoft.com/
You can run it in demo mode to see if you can find your files, you pay for it when you decide to actually recover them, good feature!
Most important for you immediately, is do not do anything to the drive! Your files are there, but they can and will get over-written. Don't install system software, don't even boot from it!