well, the obvious thought is to try photoshop on the HD2000 and see if that does the trick for you. I think it probably will do the trick if the most demanding thing is occasional photoshop. The HD2000 really isnt all that bad for integrated graphics.
The WEI is more concerned with the tech level of your hardware, not necessarily the speed or performance of that hardware. For example, a duel core CPU will ALWAYS get a lower score than a quad core, even if you are matching up an old slow quad core to a overclocked duel core that will run circles around the quad in most day-to-day use. Or a newer slow GPU will beat out a faster old one if the slow one supports DX11 and the fast one does not. In this case the HD2000 is slower but more modern, and the 430 is a little older but a little faster.
Also, the 64bit is the ram bandwidth of the onboard memory. there is not a huge difference between the 64bit bus and the 128bit bus as it is a low end GPU. I would likely return it and stick with the onboard graphics just from a simplicity standpoint. Sure the 430 is probably a little better, but it is one more fan, one more card, and a little more juice for a very marginal performance gain.
Instead of the GPU you should return it and get an SSD on sale if you dont already have one. It will open those office apps instantly, and dramatically cut down that photoshop load time