[CentOS] LVM newb needs assistance

[Allie Daneman]

I'm new to Linux and LVM coming from a BSD and Solaris background so I
apologize up front if there are good docs for this that I'm missing. After
googling around and going through the LVM Admin docs for CentOS I have a
few questions about an issue I have.

Somehow either I did it out of stupidity or the installer automagically
installed LVM and included both drives I have on this server. It's
configured as 1 Volume group and 1 huge drive so most of the docs on LVM
I've seen don't jive. Here's my pvdisplay:
   --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               VolGroup00
  PV Size               148.91 GB / not usable 4.15 MB
  Allocatable           yes (but full)
  PE Size (KByte)       32768
  Total PE              4765
  Free PE               0
  Allocated PE          4765
  PV UUID               DOv3Cl-LWoU-JG04-PT0P-VfIV-89p2-yrdnbp

  --- Physical volume ---
  PV Name               /dev/sdb1
  VG Name               VolGroup00
  PV Size               149.05 GB / not usable 17.13 MB
  Allocatable           NO
  PE Size (KByte)       32768
  Total PE              4769
  Free PE               0
  Allocated PE          4769
  PV UUID               LK017x-dWzY-KIGL-kfOr-687Z-DgEn-YMfOw5

As you can see it seems like there's no room...but here's my df print:
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      288G  170G  104G  63% /
/dev/sda1              99M   31M   64M  33% /boot
tmpfs                 315M     0  315M   0% /dev/shm
/dev/sdc1             230G  134G   85G  62% /ext_drive

So I'm running out of room and wanting to move all data to my main drive
so I can replace the 2nd drive with a bigger one. When I try a pvmove it
states I have no room:
pvmove -v /dev/sdb1
    Finding volume group "VolGroup00"
  No extents available for allocation

So now I'm lost...how can I put all data on my 1st drive and unhook the
2nd from LVM to replace it ? Any assistance is greatly appreciated. I'm
installing system-config-lvm hoping the GUI may help me as well.