Depends on the video card... However, the point of the A8 (and the entire APU line) is that they have a 'dedicated GPU' built in. That cpu is almost exactly what you currently have. It would be a waste (imo) if you got that and intended to get a discrete GPU. You may as well just get the GPU and call it a day. Lower end video cards (7770 or maybe even 7850) could probably be supported without an upgrade for a Dell 300w.
E2-3200 = Llano 2 Core 2.4ghz
A8-3829 = Llano 4 Core 2.9ghz + 6550D