U can use Partition Magic, it'll do the job perfectly!
Run the program and it'll show ur existing 3 partitions in the list.
1.) Right-click on C: Drive and select
Resize/move option and decrease it size according to ur requirements!
2.) Now right-click on the other partition, to which u want to allocate the free area and select again
Resize/move option and increase its size!
Finally click on Apply button!