I can't seem to find any specs on that model. That said, I suspect you don't have a dedicated graphics expansion slot.
If I am correct then you would need to install a PCI slot type graphics card. Low end PCI graphics cards are not terribly expensive. That said, eMachines are notorious for their terrible power supplies.
Do you have any documentation for that computer?
I am not being very helpful and I apologize for that.
In what country do you live?