Need to replace my video card?

I own a EMachine T3958,I need to replace my video card,my computer came with 128mb video card.I know the type of card I need to purchase,my question is,will a video card with 256 mb work for me?I was told if the memory was 512,you can upgrade your video with no problem,as long as it doesn't exceeds the memory.Can someone answer my question?|||256 will work fine. PCI slot? Upgrading will only help so much. (thats if its a pci slot)|||If your motherboard has intergrated video, it "borrows" from the onboard RAM. But since your v-card has its own memory, it doesn't need to ask your system to share its memory. The bottom line is get as much memory, both RAM and on your video card, as your budget and motherboard can handle.|||This card should not be any problem. Hopefully, the EMachine power supply is sufficient. Check out how many watts that power supply is putting out by looking on the back of it. Compare with the power requirements of the card you want.