hi,
i have an Acer Power sk50 with 80GB hard drive, intel celeron D 3.20Ghz processor, 2GB Ram and a 946Gz chipset.

i want to put a graphics card in it like (128 - 256MB DDR2) but i donno if it will support it....

it has a intel graphics media accelerator 3000 built in grapihcs which has an option of getting a PCI Express x16 support card.

i dont know if that will help that much, i wanna be able to play resonable games. E.g halo or somthing that will have round 64 to 128MB graphics recommedation.

so if anyone could help to find out if its already good enough pc or if not, does my pc support these graphics cards?????

According to this page, your motherboard will support a new graphics card just fine. Check your motherboard manual for procedures.

One thing you do need to worry about is power. Graphics cards can easily consume more power than your CPU. Use the eXtreme PSU Calculator Lite to determine your power supply unit (PSU) requirements. Plug in all the hardware you think you might have in 2 or 3 years (extra drives, bigger or 2nd video card, more RAM, etc.). Be sure to read and heed the notes at the bottom. I recommend you set Capacitor Aging to 30%, and if you participate in distributive computing projects (e.g. BOINC or Folding@Home), I recommend setting TDP to 100%. Research your video card and pay particular attention to the power supply requirements for your card listed on your video card maker's website. Then look for power supply brands listed under the "Good" column of PC Mechanic's PSU Reference List. Ensure the supplied amperage on the +12V rails of your chosen PSU meets the requirements of your video card. Don't try to save a few dollars by getting a cheap supply. Digital electronics, including CPUs, RAM, and today's advanced graphics cards, need clean, stable power. A good, well chosen supply will provide years of service and upgrade wiggle room. I strongly recommend you pick a supply with an efficiency rating equal to, or greater than 80%. Look for the 80 Plus - EnergyStar Compliant label. And don't forget to budget for a good UPS with AVR (automatic voltage regulation).