dual booting linux and vista, how do I make one partition bigger?

I am dual booting vista and linux mint. I have the C: drive and D: drive. Vista is on the C: drive and linux on the D:. The problem is the C: drive is approx. 140 gigs, and the D: drive is only 7gigs. I want to make the drive for windows only 30 or so and the rest for linux, but I can't shrink the C: drive. When I go to disk management it just wont let me shrink it.

You could try resizing the partition using GParted, thats possible http://gparted.sourceforge.net/

Download the ISO and create a Bootable Disc.

LUg.

NEW NIB 140 Burton Mint Snowboard Boots US 4 UK 25 Euro 34 Mondo 21 $99.99 Time Remaining: 3d 3h 21m Buy It Now for only: $99.99

NEW NIB 140 Burton Mint Snowboard Boots US 5 UK 3 Euro 35 Mondo 22 $99.99 Time Remaining: 4d 21h 3m Buy It Now for only: $99.99

NEW NIB 140 Burton Mint Snowboard Boots US 55 UK 35 Euro 36 Mondo 225 $99.99 Time Remaining: 5d 21h 45m Buy It Now for only: $99.99

NEW NIB 140 Burton Mint Snowboard Boots US 6 UK 4 Euro 365 Mondo 23 $99.99 Time Remaining: 6d 22h 56m Buy It Now for only: $99.99