Updating motherboard.. compatibility issues?

hey everyone,

im pretty good with computers, but not so much the actual hardware part of them yet. you guys are the best so i figured id run it by to see watcha think.
i started by wanting to upgrade my graphics card, and one of my teachers at school had an extra ATI kickin aroudn and i looked up the specs for it adn it soudned better than my regular one so i took it home to try it. Opened up the computer to realize.. i dotn have a slot. The graphics now is built into the motherboard and thers no AGP slot. so since im goign to end up upgrading mroe thigns, i decided i would start with gettign a new motherboard. sicne money is tight im going to have to just get the motherbaord for now, and use the rest of the current hardware.

so basically im just wondering if this will work. i have talked to soemone who said yes and steared me i nteh right direction, but never too mcuh info. im super willign to learn more so lemem know wat u think..

the motherboard i was looking at..
ASUS "P4P800-VM" i865G Chipset Motherboard for Intel Socket 478 CPU, Model -RETAIL
- Specifications -
Supported CPU:Intel Pentium 4(Hyper-Threading)/Celeron Processors
Chipset: Intel 865G + ICH5
FSB: 800/533/400MHz
RAM: 4x DIMM for Dual Channel Non-ECC DDR400/333/266 Max 4GB
IDE: 2x UltraDMA 100 up to 4 Devices
Slots: 1x AGP 8X, 3x PCI
Ports: 2xPS2,1xVGA 1xCOM,1xLPT,1xLAN,8xUSB2.0(Rear 4),Audio Ports
Onboard Audio: AD1980 6-Channel Codec
Onboard Video: Intel Extreme Graphics 2
Onboard LAN: Intel 10/100Mbps Fast Ethernet
Onboard SATA: 2x Serial ATA
Form Factor: Micro ATX


my computer stats..
its an emachines T2792
Computer:
Operating System Microsoft Windows XP Home Edition
OS Service Pack Service Pack 2
Internet Explorer 6.0.2900.2180

Motherboard:
CPU Type Intel Celeron 4A, 2700 MHz (6.75 x 400)
Motherboard Name Unknown
Motherboard Chipset Intel Brookdale-G i845G
System Memory 253 MB (PC2700 DDR SDRAM)
BIOS Type Phoenix (10/02/03)
Communication Port Communications Port (COM1)
Communication Port ECP Printer Port (LPT1)

Display:
Video Adapter Intel(R) 82845G/GL/GE/PE/GV Graphics Controller (64 MB)
3D Accelerator Intel Extreme Graphics
Monitor IBM 2124 (751385078)

Multimedia:
Audio Adapter Intel 82801DB(M) ICH4(-M) - AC'97 Audio Controller [B-0]

Storage:
Floppy Drive Floppy disk drive
Disk Drive SAMSUNG WINNER-3 WN32543A(2.5GB) (2 GB, 5400 RPM, Fast ATA-2)
Disk Drive WDC WD800EB-11DJF0
Optical Drive ATAPI CD-ROM DRIVE-32X (32x CD-ROM)
Optical Drive LITE-ON COMBO LTC-48161H (DVD:16x, CD:48x/24x/48x DVD-ROM/CD-RW)

Partitions:
C: (NTFS) 76316 MB (62830 MB free)

Input:
Keyboard Standard 101/102-Key or Microsoft Natural PS/2 Keyboard
Mouse Logitech USB WheelMouse

Network:
Network Adapter Realtek RTL8139/810X Family PCI Fast Ethernet NIC (24.131.162.248)
Modem Conexant SoftK56 Modem(M)

Peripherals:
Printer HP DeskJet 870Cse
USB Device Logitech USB WheelMouse


if you need any other info jsut let me know