Testdisk...
The standard program for recovering linux partition tables is Testdisk. If you thereby also change the partition table as it is read under Windows, you may find that Windows will not boot and you will have to repair its boot loader.
http://www.cgsecurity.org/wiki/TestDisk
Testdisk is also included on partitioning and rescue live-cds such as PartedMagic. If the missing data on the disk is important to you, think about making a clone copy of the disk before you begin to do any work on it.