video card

i wanted to upgrade my video card on emachine 2615 and i was wondering if i needed something special.

“You can purchase a PCI or AGP video card and it should install with no problems.
When purchasing the card you will need to check with the manufacturer to make
sure the card does not support multi monitor/video and is capable of disabling
onboard video. Also you will need to check the power supply requirements of the
card as some require high output power supplies.”

that was what the emachine people told me
what kind of card should i get?