Urgent: About Using idle disk space

Urgent: For details about how to use idle disk space-general Linux technology-Linux technology and application, refer to the following. The situation is as follows:
My computer is installed with dual-system, Windows & Linux Ubuntu. But when I first installed Ubuntu, I chose manual partitioning. The partition information is as follows:
/Dev/sda5 19222656 12504108 5742012 69%/
None 1024088 340 1023748 1%/dev
None 1028304 1212 1027092 1%/dev/shm
None 1028304 84 1028220 1%/var/run
None 1028304 0 1028304 0%/var/lock
None 1028304 0 1028304 0%/lib/init/rw
/Dev/sda1 41945680 23329320 18616360 56%/media/system _
/Dev/sda3 22065968 10951388 11114580 50%/media/study _
/Dev/sda2 83967996 74518444 9449552 89%/media/enter _
A total of GB hard drives on my computer. sda1 ~ 3 is a Windows partition, and the sum is 150 GB. however, when I allocate an extended area, I only allocated 20 GB instead of allocating all the remaining 320G-150G = G. currently, only one ?? Zone sda5. I hope to split the remaining 170G-20G = G space into another sda6 space. I don't want to reinstall the system. What should I do? Because the computer cannot see the remaining GB space ..
Device Boot Start End Blocks Id System
/Dev/sda1*1 5222 41945683 + 7 HPFS/NTFS
/Dev/sda2 5223 15676 83968000 7 HPFS/NTFS
Partition 2 does not end on cylinder boundary.
/Dev/sda3 15676 18423 22065975 + 7 HPFS/NTFS
/Dev/sda4 18423 21098 21483521 5 Extended
/Dev/sda5 18423 20855 19530752 83 Linux
/Dev/sda6 20855 21098 1951744 82 Linux swap/Solaris