How to set screen resolution in Ubuntu 12.04 LTS Server?

Question

I have installed Ubuntu Server 12.04 LTS 64 bit on a machine with:

1. Mother Board -- INTEL S1200BTS
2. CPU -- XEON E3 1220V3
3. HDD -- 1TB Seagate SATA
4. RAM -- Transcend 16GB DDR3

I have installed GUI(GNOME Desktop) through following commands:

sudo apt-get update
sudo apt-get install ubuntu-desktop

At present the screen resolution is set to 800x600. I am not able to set the screen resolution to 1024x768 or higher.

I tried to download display drivers from INTEL website but drivers available only for Red Hat and SUSE Linux.

I have tried following commands (shown below with their output):

root@ubuntu:~# xrandr
Screen 0: minimum 128 x 128, current 800 x 600, maximum 800 x 800
LVDS connected 800x600+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   800x600        59.9*
root@ubuntu:~# cvt 1024 768
# 1024x768 59.92 Hz (CVT 0.79M3) hsync: 47.82 kHz; pclk: 63.50 MHz
Modeline "1024x768_60.00"   63.50  1024 1072 1176 1328  768 771 775 798 -hsync +vsync
root@ubuntu:~# xrandr --newmode "1024x768_60.00"   63.50  1024 1072 1176 1328  768 771 775 798 -hsync +vsync
root@ubuntu:~# xrandr --addmode LVDS 1024x768_60.00
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  149 (RANDR)
  Minor opcode of failed request:  18 (RRAddOutputMode)
  Serial number of failed request:  20
  Current serial number in output stream:  21

How can I set the screen resolution?