Yes, you can use a PCI card, if you can find one. Now, since there are several different models of the A8V, I can't be sure that you're specific board (because you didn't list the full model number) has support for PCI-E x16.
Check your mobo manual, or look it up online. If your graphics port is AGP x8, then that is the type of graphics card you need. If your graphics port is PCI-E x16, then you could use one of those.
You should note, though, that even if your mobo can support a PCI-E x16 card, your CPU and RAM will be what bottlenecks your system. Of course, this is assuming that you're looking to upgrade to a dedicated GPU vs onboard.