Partition Limitation Problems

[gringoarenoso]

So, I've been trying to partition my hard drive to install windows 7. When I look at space available on my hard drive I have over 100GB ready and waiting. When I go into Disk Utility however, it will only let me make a second partition of 50GB and I cannot resize my primary HD. On top of that, if I start to use the BootCamp Assistant, it will only let me make a 20GB partition for Windows 7. Does anyone know what I need to do to gain access to the room I have on my HD or should I back up the things I want and format my HD and start from the beginning, only putting back the things I use? Any help would be much appreciated! Attached are some pictures giving at least some explanation of what I'm trying to say. Thanks.