I had an external harddrive that went corrupt.

(Dont ever get a Simpletech 1TB)
I was able to do a chkdsk /R and get the drive back to readable but now MOST the .jpg files on the drive are coming up corrupt. The files seem to be there but when I try to open them they show errors in all the different image viewers I have including photoshop.
HELP!

This is over two weeks of work I have done to compile all these images. Does anyone know any good (and cheap) programs that work well to recover the images.
Thanks in advance for any help...